M O R P H O L O G Y OF T H E E P I T H E L I A L C O M P O N E N T OF HUMAN LUNG HAMARTOMAS Jos@h S. Incze, M.D.,* and Peter S. Lui, M.A.'?
Abstract Unusual tfltrastructural bodies were f o u n d in a b o u t one-fifth o f the epithelial cell nuclei in t h r e e cases o f p u l m o n a r y h a m a r t o n t a . T h o s e bodies o f t e n a p p e a r to be twisted tubules with recognizable branching. Morphologically different s t r u c t u r e s are also seen in occasional nuclei. A h h o u g h the n a t u r e a n d significance o f the bodies are obscure, they m a y r e p r e s e n t different stages o f d e v e l o p m e n t o f the s a m e structure. Similar bodies have not b e e n e n c o t m t e r e d to date in any o f o u r o t h e r e x a m i n a t i o n s o f epithelial cells.
T h e classic concept o f h a m a r t o m a s is that these lesions r e p r e s e n t an o v e r g r o w t h o f a tissue tlmt is n o r m a l l y e n c o u n t e r e d in tlmt location o f the body. T h e cells app e a r to be m a t u r e , but the a m o u n t o f tissue is increased and its a r r a n g e m e n t is abnormal, t'2 T h e l m n t a r t o m a s m a y be c o m p o s e d o f a single type o f tissue o r m a y show a m i x t u r e o f tissues with predonfinance o f o n e or a n o t h e r c o m p o n e n t . T h e p r e d o m i n a n t tissue in l u n g h a n m r t o m a s is cartilage, b u t muscle, nerve, a n d fat are often p r e s e n t ? -'a We h a v e recently lind the o p p o r t u n i t y to study the u l t r a s t r u c t u r e in tin'ee cases of surgically resected p u l m o n a r y I m m a r toma. In the material p r e s e n t e d h e r e e p i t h e l i u m was always p r e s e n t a l o n g with cartilage. A l t h o u g h we have described the fine structures o f these lesions, we lmve
c o n c e n t r a t e d o u r effort in the study o f the epithelial c o m p o n e n t .
MATERIAL AND METHODS In o u r 600 b e d hospital o v e r a six m o n t h period, t h r e e surgically resected cases o f p u l m o n a r y h a m a r t o m a were e n c o u n t e r e d . O u r three patients w e r e males in their sixth decade. All were admitted for an a p p a r e n t l y u n r e l a t e d condition a n d the lesions were discovered on r o u t i n e x-ray e x a m i n a t i o n . T h r e e consecutive surgical cases w e r e e x a m i n e d . T h e tissue collected d u r i n g t h o r a c o t o m y was s u b m i t t e d for diagnostic frozen section examination. Fresh tissue was fixed within a few minutes a f t e r r e m o v a l (an a v e r a g e o f five minutes a f t e r
*Associate Clinical Professor, Deparunent of l'athology, Tufts University School of Medicine. Staff, Department of l'athologT, Veterans Administration Hospital, Boston, Massachusetts. "tConsultant Electron Microscopist, Department of l'athology, Tufts University School of Medicine. Research Associate, Department of Patholo~', Veterans Administration tlospital, Boston, Massachusetts.
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HUMAN PATHOLOGY--VOLUME 8, NUMBER-4 July 1977 resection) and was divided for light and electron microscopic specimens. For light microscopy the usual buffered formalin fixation and paraffin embedding were used. For electron microscopic studies 2.5 per cent glutaraldehyde in phosphate buffer was used. T h e tissue was postfixed in osmic acid, dehydrated, and embedded in Epon. After staining with uranyl acetate and lead citrate the sections were examined with a Phillips 300 electron microscope. T h e usual dark room technique was followed. RESULTS
Gross Findings T h e tissue submitted in all these cases was scanty, and no diagnostically characterictic gross findings were described. All three specimens were subpleural and the covering pleura was shiny and thin. The pleural aspect was slightly dented, probably as a result of compressiort by the overlying rib, but none of the lesions was adherent to the rib cage. Depending on the amount and distribution of the cartilaginous component, the tissue was variably firm and in cartilaginous areas shiny and somewhat translucent. T h e predominating color was grayish pink.
Light Microscopy
412
T h e findings were similar to those described in several textbooks and papers? -9 In all cases we were able to find an epithelial component. The epithelium was usually a monolayer, but in some places two to three layers of cells were seen (Fig. 1A). The cells were of epithelial cha1:acter, closel), resembling respiratory epithelium. In several of the epithelial cell nuclei a central light area was seen that was almost homogenous but suggested a lacy, multiloculated area distinguishable from the rest of the nuclear material (Fig. 1B). T h e amount of epithelium varied considerably. In one case only a few epithelial cells were found; in the second specimen about 5 to 10 per cent of the tissue was composed of epithelial cells,
whereas 20 per cent of the cell mass of the third specimen was represented by epithelium. T h e rest of the tissue in these lesions was composed mostly of mature stroma containing cartilage, nerve, and fat.
Ultrastructural Findings Electron microscopic examination of tile epithelium revealed a limiting basement membrane upon which the cells were arranged in a fairly regular fashion (Fig. 2A). From the luminal surface numerous microvilli emerged. The intercellular spaces often contained microvilli, but the neighboring cells were usually tightly connected, although only an occasional small desmosome was noted (Fig. 2B). A fair number of mitochondria with moderately severe degenerative changes were present in the cytoplasm of the epithelial cells, together with a few Iysosomes, occasional vacuoles, and many profiles of rough endoplasmic reticulum, some taking twisted, curved, or curled shapes with focal areas of dilatation of the cisternae and scattered ribosomes. In other areas the endoplasmic reticulum cisternae appeared compressed. Some cells also contained secretory granules and many myelin-like bodies in those epithelial cells having the unusual nuclear bodies to be described (Fig. 2A, C). Common nuclear structures of epithelial cells in hamartomas such as interchromatin granules as well as structures resembling perichromatin granules and obvious nucleoli were easily identifiable. In about 10 per cent of the epithelial cells unusual nuclear structures were found. T h e most striking of them were well circumscribed but had no limiting membranes. These structures were so large that they occupied close to half the nuclear mass. The nuclear bodies either lay in the center of the nucleus or were eccentrically placed (Fig. 1B). We have never found a direct connection between the bodies and either the nuclear membrane or the perinuclear space. T h e content of these areas was not homogenous, but neither was it similar to that of any of cytoplasmic organelles. These bodies
HUMAN I.UN(; HAMARTOMAS-INczE,-Lu~ limited by a simple m e m b r a n e , but when these were adjacent to each other, the limiting m e m b r a n e a p p e a r e d doubled. Some o f the hollow structures, mostly the large a n d a l m o n d s h a p e d ones, contained d e t a c h e d m e m b r a n e s , crossing the vacuole a n d subdividing it into elongated muhicompartmented units. The adjacent structures o f t e n were elongated. T h e c u r v e d walls sometimes a p p e a r e d straight,
were c o m p o s e d mostly o f r o u n d o r oval structures varying in shape a n d size; occasionally a h n o n d shaped bodies were also f o u n d and these t e n d e d to be larger than the oval a n d r o u n d bodies. O n section the bodies often a p p e a r e d as hollow or tubular structures, which seemed to contain a finely dispersed material in their lumina (Fig. 2C). T h e individual hollow structures were
,
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Figure 1. A, Light microscopic photograph showing a combination of epithelial cells, fibrous stroma, and lymphoid tissne. B, Light microscopic photograph showing several epithelial cells with nuclei exhibiting a light center with a recognizable strncture. L, lumen. IS, intercellular space. Arrows indicate intranuclear circumscribed hollow structure. (A, ttematox)'lin and eosin stain. • 120.B, Unstained. Epon section phase. X4000.) 4 1 3
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Figure 2, Epithelial cell component of hamartomas. A, One layer of epithelial cells on basement nlembrane (B), showing lumen (L), intercellular space (IS), microvilli (MV), secretory granules (SG), and Golgi-complex (G). B, Pseudostratification of epithelial cells. IS, intercellular space. MY, microvilli, D, ttesmosome. N, nucleus. C, l'seudostratified epithelial component. Nuclei show lacclike intranuclear structure (large arrow). N, nucleus. NU, nucleolus. MV, microvilli. Thin arrows, intranuclear and intrac)'toplasmic cleftlike structures. ML, m)'elinlike body, (d, x 7800, B, x 6600. C, x 6600.)
IIUMAN
LUNG HAMARTOMAS-I.~czE,
LuI
Figure 3. Details of intranuclear bodies of epithelial ceils. Note that there is no limiting membrane. T h e r e is a double limiting wall of ringlike structures (arrows). CIt, chromatin. CF, intranuclear cleft. (• 70,000.)
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HUMAN PATtlOLOGY-VOLUME 8, NUMBER 4 July 1977 giving the impression that the vacuoles were compressed. Some of these spaces assumed a cleft shape (Fig. 3). Sometimes the transition between tiffs region and the remainder of the nucleoplasm was not abrupt, but there was a gradual transition between the nucleoplasm and the tubular structure. At the margins of the inclusions, some o f the rings and tubules penetrated the nucleoplasm f o r a short distance (Figs. 4, 5). These tubular structures not only were twisted and curved but occasionally exhibited recognizable branching (Figs. 3 to 5). The tubules when extremely dilated tended in part to lose the limiting membrane and the detached membrane subdivided the round or elongated lumen. In an occasional nucleus other intranuclear bodies were found that were much smaller than tire ones just described. These appeared to be ill defined areas composed of microfilaments (Fig. 6). These bodies were occasionally present
along with a cytoplasmic invagination (Fig. 6A). The invaginations containing finely granular material were bordered by a simple membrane. The elongated, often almond shaped areas were composed of roughly parallel filamentous structures of essentially even diameter measuring 10 to 20/~ (Fig. 6B). Sometimes the filaments exhibited one to four nodular densities with a relatively consistent Size averaging 25 ,~ in diameter (Fig. 6C). These regular nodular densities caused the filaments to appear beaded. These benign tumors, which often are diagnosed only during or after thoracotomy, seldom are symptomatic and are usually discovered on a routine x-ray examination. They may cause concern and uncertainty. During the last few years their numbers have been apparently increasing, probably because of better diagnostic methods and increased interest in early discovery o f pulmonary malignant tumors. From our several cases of pulmonary
Figure 4. lntranuclear body shows a tubular component, exhibiting twisting and branching, r~ poorly defined border appears between the nuclear body and the nucleoplasnl (area between facing arrows). CH, 4 ] 6 chromatin. NM, nuclear membrane. (• 70,000.)
HUMAN LUNG HAMARTOMAS-INczE, Lul
Figure 5. Twisted tubular structures ('IT) with branching (arrows). Ctt, chromatin. (x 70,000.)
h a m a r t o m a s we have studied with tim ultramicroscope tile t h r e e most recent surgically resected lesions. Although tile h a m a r t o m a s in all t h r e e cases r e p o r t e d h e r e did not a p p e a r unusual by light microscopy and c o n f o r m e d to descriptions f o u n d in s t a n d a r d texts, ~-4 electron microscopy disclosed some unusual findings. T w o types o f intranuclear inclusions were f o u n d that to o u r knowledge have n e v e r been previously described in h a m a r t o m a s o f tile hmg. Tile most striking inclusion took tile f o r m o f an egg shaped, multilobulated, c o m p a r t m e n t e d body. Tile second, smaller in overall size, a p p e a r e d to be an aggregate o f thin fibrils r u n n i n g parallel with each other, f o r m i n g an egg shaped, indistinctly defined area. S o m e o f the small structures were f o r m e d o f fibrils o f even diameter, whereas others were c o m p o s e d o f beaded fibrils. Because o f the differing fibrillary c o m p o n e n t s , these fibrillary bodies a p p e a r e d to r e p r e s e n t m o r p h o logically different cell c o m p o n e n t s . T h e
two ill defined fibrillary bodies wm:e very similar. T h e r e is o n e r e p o r t o f circumscribed nuclear bodies in an alveolar cell carcinoma. 5 This s t r u c t u r e differs f r o m o u r finding in that the illustrated r o u n d o r oval bodies were m e m b r a n e limited. Memb r a n e limited, seemingly intranuclear bodies were o f t e n f o u n d , but m a n y o f t h e m r e p r e s e n t only invagination o r herniation o f cytoplasm containing organelles. T h e s e bodies were limited by the nuclear m e m b r a n e . We f o u n d similar structures (Fig. 6A). What provokes the production o f tile nuclear bodies is difficult to say. In general tim nuclei o f tile epithelial cells o f o u r t h r e e p u l m o n a r y h a m a r t o m a s had characteristics o f both benign and malignant lesions o f the hmg. W e have not seen these unusual intranuclear structures in any o f tile nuclei o f l y m p h o i d tissue, cartilage, fat, or n o r m a l bronclfial epithelium that we have e x a m i n e d to date. We have seen filamentous material previously in t u m o r
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Figure 6. Nucleus of epithelial cell. A, Large invagination, melnbrane bordered (IX'). Two imranuclear bodies different in appearance. Fine filaments (large arrow) and beaded filanlents (double arrow). B, Detail of coqtent at large arrow in A, showing fine filaments (arrow) and chromatin (Ctl). IV, membrane of invagination. C, Detail of con: qnt at double arrow in A, showing beaded filaments (arrow), chromatin (CI t), and membrane of invag,'ination (IV). (A, x 50,000. B and C, x 99,000.)
I I U M A N LUNG H A M A R T O M A S - I x c z E , Lu1 nuclei. S t r u c t u r e s s o n m w h a t similar to o u r s were r e c e n t l y f o u n d in nuclei o f circnlating l y m p h o c y t e s in cases o f nmltiple sclerosis a n d optic neuritis. T h e filam e n t s f o r m i n g the bodies d e s c r i b e d by ns, h o w e v e r , a r e finer, n O n e can s p e c u l a t e as to w h e t h e r t h e s t r u c t u r e s d e s c r i b e d r e p r e sent a r e a c t i o n to solne e x o g e n o u s irritant, such as an a n t i g e n o r a bacterial o r viral toxin, o r w h e t h e r t h e y r e p r e s e n t a d e g e n erative c h a n g e . T h e y d o n o t have the clmracteristics o f a n y c o m m o n viral o r bacterial particle. T h e fact t h a t m u h i p l e morphologically different structures were s o m e t i m e s p r e s e n t in tim s a m e n u c l e u s suggests t h a t t h e y m a y be basically identical a n d r e p r e s e n t d i f f e r e n t d e v e l o p m e n t a l stages (Fig. 6A). T h e s e i n t r a n t t c l e a r bodies m a y m e r e l y be m a n i f e s t a t i o n s o f the a g i n g process o f tim cell. T h e t u r n o v e r o f these cells m u s t be slow as i n d i c a t e d by g r a d u a l i n c r e a s e in the size o f t h e lesion. T h e f i n d i n g o f n u m e r o u s myelin-like bodies also s o m e w h a t s u p p o r t s this s p e c u lation. A l t h o u g l l we have e x a m i n e d o n l y t h r e e cases, the p r e s e n c e o f t h e s e intran u c l e a r inclusions in all t h r e e suggests tlmt these n u c l e a r bodies m a y be a c o n s t a n t a n d p a t h o g n o n m n i c c o m p o n e n t o f the epithelial cell nuclei o f p u l m o n a r y h a m a r tomas.
ACKNOWLEDGMENT W e wish to t h a n k Dr. S. Robbins, Chairman, Department of l'athology,
B o s t o n University, a n d Dr. L. D. B e r m a n , C h i e f o f tim L a b o r a t o r y Service, V e t e r a n s Administration Hospital, Boston, f o r r e v i e w i n g the m a n u s c r i p t a n d for valuable support and suggestions.
REFERENCES 1. Robbins, S. L.: PathologT. Ed. 3. l'hiladelphia, W. B. Saunders Company, 1967, p. 759. 2~. Ackerman, L. V., and Rosai, J.: Surgical l'athology. Ed. 5. St. Lonis, Tile C. V. Mosby Company, 1974, p. 221. 3. Kaplan, C., Katoh, A., Shamoto, M., Rogow, E., Scott, J. tt., Cushing, W., and Cooper, J.: Muhiple leiom)omas of tim hmg; benign or nmlignant. Am. Rev. Resp. Dis., 108:656, 1973. 4. Del Pozo, E., and Mattei, I. R.: Muhiple pulmonary leionD'omatous hamartomas. Am. Rev. Resp. Dis., 100:388, 1969. 5. Sulcer, H . , et al.: Multiple leiomyomatous haumrtoma of tim lung. Sch.weiz. Med. Wschr., 105:56. 1975. 6. Delmer, L. P., Ewing, S. L., and Sumner, It. W.: Infantile mesenchymal Immartoma of tim liver. Arch. Path., 99:379, 1975. 7. Silverbere, S. G.: Adenomatosis ofendometrium and endocervix-a hamartoma. Am. J. Path., 64:192, 1975. 8. Garcia-Bynuel, R., et al.: John ltopkins Med. J., 127:213, 1970. 9. Roy, A. D., and Bremner, A. D.: Epithelial hamartoma of the liver. Brit. J. Surg., 58:405, 1971. 10. Shah, B. K., Unger, L., Heinlich, H. S.: Hamartoinatous polyp of esophagus. Arch. Surg., 110:326, 1975. 11. Tanaka, R., Santoli, D., and Koprowski, H.: Unusual intrannclear filaments in the circtdating lymphocytes of patients with multiple sclerosis and optic neuritis. Am. J. l'ath., 83:254, 1976. Del)artment of l'athology Veterans Administration Hospital 150 South Huntington Avenue Boston, Massaclmsetts 02130 (Dr. Incze)
419
Abstract Unusual tfltrastructural bodies were f o u n d in a b o u t one-fifth o f the epithelial cell nuclei in t h r e e cases o f p u l m o n a r y h a m a r t o n t a . T h o s e bodies o f t e n a p p e a r to be twisted tubules with recognizable branching. Morphologically different s t r u c t u r e s are also seen in occasional nuclei. A h h o u g h the n a t u r e a n d significance o f the bodies are obscure, they m a y r e p r e s e n t different stages o f d e v e l o p m e n t o f the s a m e structure. Similar bodies have not b e e n e n c o t m t e r e d to date in any o f o u r o t h e r e x a m i n a t i o n s o f epithelial cells.
T h e classic concept o f h a m a r t o m a s is that these lesions r e p r e s e n t an o v e r g r o w t h o f a tissue tlmt is n o r m a l l y e n c o u n t e r e d in tlmt location o f the body. T h e cells app e a r to be m a t u r e , but the a m o u n t o f tissue is increased and its a r r a n g e m e n t is abnormal, t'2 T h e l m n t a r t o m a s m a y be c o m p o s e d o f a single type o f tissue o r m a y show a m i x t u r e o f tissues with predonfinance o f o n e or a n o t h e r c o m p o n e n t . T h e p r e d o m i n a n t tissue in l u n g h a n m r t o m a s is cartilage, b u t muscle, nerve, a n d fat are often p r e s e n t ? -'a We h a v e recently lind the o p p o r t u n i t y to study the u l t r a s t r u c t u r e in tin'ee cases of surgically resected p u l m o n a r y I m m a r toma. In the material p r e s e n t e d h e r e e p i t h e l i u m was always p r e s e n t a l o n g with cartilage. A l t h o u g h we have described the fine structures o f these lesions, we lmve
c o n c e n t r a t e d o u r effort in the study o f the epithelial c o m p o n e n t .
MATERIAL AND METHODS In o u r 600 b e d hospital o v e r a six m o n t h period, t h r e e surgically resected cases o f p u l m o n a r y h a m a r t o m a were e n c o u n t e r e d . O u r three patients w e r e males in their sixth decade. All were admitted for an a p p a r e n t l y u n r e l a t e d condition a n d the lesions were discovered on r o u t i n e x-ray e x a m i n a t i o n . T h r e e consecutive surgical cases w e r e e x a m i n e d . T h e tissue collected d u r i n g t h o r a c o t o m y was s u b m i t t e d for diagnostic frozen section examination. Fresh tissue was fixed within a few minutes a f t e r r e m o v a l (an a v e r a g e o f five minutes a f t e r
*Associate Clinical Professor, Deparunent of l'athology, Tufts University School of Medicine. Staff, Department of l'athologT, Veterans Administration Hospital, Boston, Massachusetts. "tConsultant Electron Microscopist, Department of l'athology, Tufts University School of Medicine. Research Associate, Department of Patholo~', Veterans Administration tlospital, Boston, Massachusetts.
411
HUMAN PATHOLOGY--VOLUME 8, NUMBER-4 July 1977 resection) and was divided for light and electron microscopic specimens. For light microscopy the usual buffered formalin fixation and paraffin embedding were used. For electron microscopic studies 2.5 per cent glutaraldehyde in phosphate buffer was used. T h e tissue was postfixed in osmic acid, dehydrated, and embedded in Epon. After staining with uranyl acetate and lead citrate the sections were examined with a Phillips 300 electron microscope. T h e usual dark room technique was followed. RESULTS
Gross Findings T h e tissue submitted in all these cases was scanty, and no diagnostically characterictic gross findings were described. All three specimens were subpleural and the covering pleura was shiny and thin. The pleural aspect was slightly dented, probably as a result of compressiort by the overlying rib, but none of the lesions was adherent to the rib cage. Depending on the amount and distribution of the cartilaginous component, the tissue was variably firm and in cartilaginous areas shiny and somewhat translucent. T h e predominating color was grayish pink.
Light Microscopy
412
T h e findings were similar to those described in several textbooks and papers? -9 In all cases we were able to find an epithelial component. The epithelium was usually a monolayer, but in some places two to three layers of cells were seen (Fig. 1A). The cells were of epithelial cha1:acter, closel), resembling respiratory epithelium. In several of the epithelial cell nuclei a central light area was seen that was almost homogenous but suggested a lacy, multiloculated area distinguishable from the rest of the nuclear material (Fig. 1B). T h e amount of epithelium varied considerably. In one case only a few epithelial cells were found; in the second specimen about 5 to 10 per cent of the tissue was composed of epithelial cells,
whereas 20 per cent of the cell mass of the third specimen was represented by epithelium. T h e rest of the tissue in these lesions was composed mostly of mature stroma containing cartilage, nerve, and fat.
Ultrastructural Findings Electron microscopic examination of tile epithelium revealed a limiting basement membrane upon which the cells were arranged in a fairly regular fashion (Fig. 2A). From the luminal surface numerous microvilli emerged. The intercellular spaces often contained microvilli, but the neighboring cells were usually tightly connected, although only an occasional small desmosome was noted (Fig. 2B). A fair number of mitochondria with moderately severe degenerative changes were present in the cytoplasm of the epithelial cells, together with a few Iysosomes, occasional vacuoles, and many profiles of rough endoplasmic reticulum, some taking twisted, curved, or curled shapes with focal areas of dilatation of the cisternae and scattered ribosomes. In other areas the endoplasmic reticulum cisternae appeared compressed. Some cells also contained secretory granules and many myelin-like bodies in those epithelial cells having the unusual nuclear bodies to be described (Fig. 2A, C). Common nuclear structures of epithelial cells in hamartomas such as interchromatin granules as well as structures resembling perichromatin granules and obvious nucleoli were easily identifiable. In about 10 per cent of the epithelial cells unusual nuclear structures were found. T h e most striking of them were well circumscribed but had no limiting membranes. These structures were so large that they occupied close to half the nuclear mass. The nuclear bodies either lay in the center of the nucleus or were eccentrically placed (Fig. 1B). We have never found a direct connection between the bodies and either the nuclear membrane or the perinuclear space. T h e content of these areas was not homogenous, but neither was it similar to that of any of cytoplasmic organelles. These bodies
HUMAN I.UN(; HAMARTOMAS-INczE,-Lu~ limited by a simple m e m b r a n e , but when these were adjacent to each other, the limiting m e m b r a n e a p p e a r e d doubled. Some o f the hollow structures, mostly the large a n d a l m o n d s h a p e d ones, contained d e t a c h e d m e m b r a n e s , crossing the vacuole a n d subdividing it into elongated muhicompartmented units. The adjacent structures o f t e n were elongated. T h e c u r v e d walls sometimes a p p e a r e d straight,
were c o m p o s e d mostly o f r o u n d o r oval structures varying in shape a n d size; occasionally a h n o n d shaped bodies were also f o u n d and these t e n d e d to be larger than the oval a n d r o u n d bodies. O n section the bodies often a p p e a r e d as hollow or tubular structures, which seemed to contain a finely dispersed material in their lumina (Fig. 2C). T h e individual hollow structures were
,
~
".'
- ."~!
~,:
--,,,~
,. ,"~n~
-,.'-', .
-.._'~.
:'-" " c . . ~ " :
. ,
w,d~-
', , s
- -. - - . - - : d ~
~**.. ':'.. ", I
-...=.~,.~,L-.~,
, ,
Figure 1. A, Light microscopic photograph showing a combination of epithelial cells, fibrous stroma, and lymphoid tissne. B, Light microscopic photograph showing several epithelial cells with nuclei exhibiting a light center with a recognizable strncture. L, lumen. IS, intercellular space. Arrows indicate intranuclear circumscribed hollow structure. (A, ttematox)'lin and eosin stain. • 120.B, Unstained. Epon section phase. X4000.) 4 1 3
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Figure 2, Epithelial cell component of hamartomas. A, One layer of epithelial cells on basement nlembrane (B), showing lumen (L), intercellular space (IS), microvilli (MV), secretory granules (SG), and Golgi-complex (G). B, Pseudostratification of epithelial cells. IS, intercellular space. MY, microvilli, D, ttesmosome. N, nucleus. C, l'seudostratified epithelial component. Nuclei show lacclike intranuclear structure (large arrow). N, nucleus. NU, nucleolus. MV, microvilli. Thin arrows, intranuclear and intrac)'toplasmic cleftlike structures. ML, m)'elinlike body, (d, x 7800, B, x 6600. C, x 6600.)
IIUMAN
LUNG HAMARTOMAS-I.~czE,
LuI
Figure 3. Details of intranuclear bodies of epithelial ceils. Note that there is no limiting membrane. T h e r e is a double limiting wall of ringlike structures (arrows). CIt, chromatin. CF, intranuclear cleft. (• 70,000.)
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HUMAN PATtlOLOGY-VOLUME 8, NUMBER 4 July 1977 giving the impression that the vacuoles were compressed. Some of these spaces assumed a cleft shape (Fig. 3). Sometimes the transition between tiffs region and the remainder of the nucleoplasm was not abrupt, but there was a gradual transition between the nucleoplasm and the tubular structure. At the margins of the inclusions, some o f the rings and tubules penetrated the nucleoplasm f o r a short distance (Figs. 4, 5). These tubular structures not only were twisted and curved but occasionally exhibited recognizable branching (Figs. 3 to 5). The tubules when extremely dilated tended in part to lose the limiting membrane and the detached membrane subdivided the round or elongated lumen. In an occasional nucleus other intranuclear bodies were found that were much smaller than tire ones just described. These appeared to be ill defined areas composed of microfilaments (Fig. 6). These bodies were occasionally present
along with a cytoplasmic invagination (Fig. 6A). The invaginations containing finely granular material were bordered by a simple membrane. The elongated, often almond shaped areas were composed of roughly parallel filamentous structures of essentially even diameter measuring 10 to 20/~ (Fig. 6B). Sometimes the filaments exhibited one to four nodular densities with a relatively consistent Size averaging 25 ,~ in diameter (Fig. 6C). These regular nodular densities caused the filaments to appear beaded. These benign tumors, which often are diagnosed only during or after thoracotomy, seldom are symptomatic and are usually discovered on a routine x-ray examination. They may cause concern and uncertainty. During the last few years their numbers have been apparently increasing, probably because of better diagnostic methods and increased interest in early discovery o f pulmonary malignant tumors. From our several cases of pulmonary
Figure 4. lntranuclear body shows a tubular component, exhibiting twisting and branching, r~ poorly defined border appears between the nuclear body and the nucleoplasnl (area between facing arrows). CH, 4 ] 6 chromatin. NM, nuclear membrane. (• 70,000.)
HUMAN LUNG HAMARTOMAS-INczE, Lul
Figure 5. Twisted tubular structures ('IT) with branching (arrows). Ctt, chromatin. (x 70,000.)
h a m a r t o m a s we have studied with tim ultramicroscope tile t h r e e most recent surgically resected lesions. Although tile h a m a r t o m a s in all t h r e e cases r e p o r t e d h e r e did not a p p e a r unusual by light microscopy and c o n f o r m e d to descriptions f o u n d in s t a n d a r d texts, ~-4 electron microscopy disclosed some unusual findings. T w o types o f intranuclear inclusions were f o u n d that to o u r knowledge have n e v e r been previously described in h a m a r t o m a s o f tile hmg. Tile most striking inclusion took tile f o r m o f an egg shaped, multilobulated, c o m p a r t m e n t e d body. Tile second, smaller in overall size, a p p e a r e d to be an aggregate o f thin fibrils r u n n i n g parallel with each other, f o r m i n g an egg shaped, indistinctly defined area. S o m e o f the small structures were f o r m e d o f fibrils o f even diameter, whereas others were c o m p o s e d o f beaded fibrils. Because o f the differing fibrillary c o m p o n e n t s , these fibrillary bodies a p p e a r e d to r e p r e s e n t m o r p h o logically different cell c o m p o n e n t s . T h e
two ill defined fibrillary bodies wm:e very similar. T h e r e is o n e r e p o r t o f circumscribed nuclear bodies in an alveolar cell carcinoma. 5 This s t r u c t u r e differs f r o m o u r finding in that the illustrated r o u n d o r oval bodies were m e m b r a n e limited. Memb r a n e limited, seemingly intranuclear bodies were o f t e n f o u n d , but m a n y o f t h e m r e p r e s e n t only invagination o r herniation o f cytoplasm containing organelles. T h e s e bodies were limited by the nuclear m e m b r a n e . We f o u n d similar structures (Fig. 6A). What provokes the production o f tile nuclear bodies is difficult to say. In general tim nuclei o f tile epithelial cells o f o u r t h r e e p u l m o n a r y h a m a r t o m a s had characteristics o f both benign and malignant lesions o f the hmg. W e have not seen these unusual intranuclear structures in any o f tile nuclei o f l y m p h o i d tissue, cartilage, fat, or n o r m a l bronclfial epithelium that we have e x a m i n e d to date. We have seen filamentous material previously in t u m o r
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Figure 6. Nucleus of epithelial cell. A, Large invagination, melnbrane bordered (IX'). Two imranuclear bodies different in appearance. Fine filaments (large arrow) and beaded filanlents (double arrow). B, Detail of coqtent at large arrow in A, showing fine filaments (arrow) and chromatin (Ctl). IV, membrane of invagination. C, Detail of con: qnt at double arrow in A, showing beaded filaments (arrow), chromatin (CI t), and membrane of invag,'ination (IV). (A, x 50,000. B and C, x 99,000.)
I I U M A N LUNG H A M A R T O M A S - I x c z E , Lu1 nuclei. S t r u c t u r e s s o n m w h a t similar to o u r s were r e c e n t l y f o u n d in nuclei o f circnlating l y m p h o c y t e s in cases o f nmltiple sclerosis a n d optic neuritis. T h e filam e n t s f o r m i n g the bodies d e s c r i b e d by ns, h o w e v e r , a r e finer, n O n e can s p e c u l a t e as to w h e t h e r t h e s t r u c t u r e s d e s c r i b e d r e p r e sent a r e a c t i o n to solne e x o g e n o u s irritant, such as an a n t i g e n o r a bacterial o r viral toxin, o r w h e t h e r t h e y r e p r e s e n t a d e g e n erative c h a n g e . T h e y d o n o t have the clmracteristics o f a n y c o m m o n viral o r bacterial particle. T h e fact t h a t m u h i p l e morphologically different structures were s o m e t i m e s p r e s e n t in tim s a m e n u c l e u s suggests t h a t t h e y m a y be basically identical a n d r e p r e s e n t d i f f e r e n t d e v e l o p m e n t a l stages (Fig. 6A). T h e s e i n t r a n t t c l e a r bodies m a y m e r e l y be m a n i f e s t a t i o n s o f the a g i n g process o f tim cell. T h e t u r n o v e r o f these cells m u s t be slow as i n d i c a t e d by g r a d u a l i n c r e a s e in the size o f t h e lesion. T h e f i n d i n g o f n u m e r o u s myelin-like bodies also s o m e w h a t s u p p o r t s this s p e c u lation. A l t h o u g l l we have e x a m i n e d o n l y t h r e e cases, the p r e s e n c e o f t h e s e intran u c l e a r inclusions in all t h r e e suggests tlmt these n u c l e a r bodies m a y be a c o n s t a n t a n d p a t h o g n o n m n i c c o m p o n e n t o f the epithelial cell nuclei o f p u l m o n a r y h a m a r tomas.
ACKNOWLEDGMENT W e wish to t h a n k Dr. S. Robbins, Chairman, Department of l'athology,
B o s t o n University, a n d Dr. L. D. B e r m a n , C h i e f o f tim L a b o r a t o r y Service, V e t e r a n s Administration Hospital, Boston, f o r r e v i e w i n g the m a n u s c r i p t a n d for valuable support and suggestions.
REFERENCES 1. Robbins, S. L.: PathologT. Ed. 3. l'hiladelphia, W. B. Saunders Company, 1967, p. 759. 2~. Ackerman, L. V., and Rosai, J.: Surgical l'athology. Ed. 5. St. Lonis, Tile C. V. Mosby Company, 1974, p. 221. 3. Kaplan, C., Katoh, A., Shamoto, M., Rogow, E., Scott, J. tt., Cushing, W., and Cooper, J.: Muhiple leiom)omas of tim hmg; benign or nmlignant. Am. Rev. Resp. Dis., 108:656, 1973. 4. Del Pozo, E., and Mattei, I. R.: Muhiple pulmonary leionD'omatous hamartomas. Am. Rev. Resp. Dis., 100:388, 1969. 5. Sulcer, H . , et al.: Multiple leiomyomatous haumrtoma of tim lung. Sch.weiz. Med. Wschr., 105:56. 1975. 6. Delmer, L. P., Ewing, S. L., and Sumner, It. W.: Infantile mesenchymal Immartoma of tim liver. Arch. Path., 99:379, 1975. 7. Silverbere, S. G.: Adenomatosis ofendometrium and endocervix-a hamartoma. Am. J. Path., 64:192, 1975. 8. Garcia-Bynuel, R., et al.: John ltopkins Med. J., 127:213, 1970. 9. Roy, A. D., and Bremner, A. D.: Epithelial hamartoma of the liver. Brit. J. Surg., 58:405, 1971. 10. Shah, B. K., Unger, L., Heinlich, H. S.: Hamartoinatous polyp of esophagus. Arch. Surg., 110:326, 1975. 11. Tanaka, R., Santoli, D., and Koprowski, H.: Unusual intrannclear filaments in the circtdating lymphocytes of patients with multiple sclerosis and optic neuritis. Am. J. l'ath., 83:254, 1976. Del)artment of l'athology Veterans Administration Hospital 150 South Huntington Avenue Boston, Massaclmsetts 02130 (Dr. Incze)
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