Acta Neuropathol (1992) 83:664 - 666
Aaa HeuropathologKa (~) Springer-Verlag1992
Case reports Intracisternal inclusions in Schwann cells of the sural nerve Hirofumi Kusaka and Terukuni Imai Department of Neurology, Kitano Hospital and Neurological Center, 13-3, Kamiyama-cho, Kita-ku, Osaka 530, Japan Received October 31, 1991; Accepted December 23, 1991
Summary. Biopsy of the sural nerve in a 74-year-old man with chronic neuropathy demonstrated Schwann cells that possessed multiple cisterns of rough endoplasmic reticulum filled with 7- to 8-nm filaments and perinuclear cisterns that were markedly distended with fine granular substances and electron-dense globules. To our knowledge, this is the third case exhibiting filamentous inclusions in Schwann cells. Unlike the previous cases, however, this case showed inclusions in the distended perinuclear cisterns and axonal degeneration. The significance of these alterations remains to be elucidated. Key words: Dutcher's bodies - Endoplasmic reticulum -
to pain and touch in a glove and stocking distribution, and mild weakness of the lower extremities and hands. CSF examination revealed a total protein of 34 rag/100 ml and 4 cells/mm3. The following laboratory tests were normal or negative: plasma vitamin Ba, B6, B12, folate, TSH, thyroxine, RBC, hematocrit, Hb,WBC, BUN, serum creatinine, CPK, immunoglobulins, cryoglobulin, and M-protein. Even on treatment with acetohexamide, his fasting blood sugar was 180, and hemoglobin Ale was 8.9 (normal: 4.0 %-6.0 %) on admission. Electrophysiological studies showed mild slowing of maximal motor conduction velocity of the tibial and peroneal nerves and mild slowing of maximal sensory conduction velocity of the sural nerve with prolonged latencies. Needle electromyographic examination revealed evidence of spontaneous activity (fibrillations) and reduced recruitment patterns with maximal voluntary effort in several muscles of the lower extremities. A biopsy of the sural nerve was performed.
Microfilaments - Perinuclear cistern - Schwann cell
Neuropathological findings Vallat et al. [13] reported unprecedented filamentous accumulation in the rough endoplasmic reticulum (rER) of myelinated Schwann cells in two cases with peripheral neuropathy. There have been no further reports of similar inclusions in Schwann cells. We recently enocuntered a patient with chronic polyneuropathy, in whom were found several Schwann cells containing filamentous accumulations in the rER, as well as granular deposits in the perinuclear cisterns.
Case report The patient had a history of poorly controlled non-insulindependent diabetes mellitus since the age of 40. He underwent partial gastrectomy for peptic ulcer at age 63, and developed unsteadiness of gait and weakness of the lower extremities at age 71. The symptoms gradually progressed and he was referred to our hospital at age 74. He drank about 100 g of alcohol daily. There was no family history of neurological disorders. Neurological examination revealed areflexia of all four extremities, symmetric vibration sense deficit particularly in the lower extremities, mild hypesthesia Offprint requests to: H. Kusaka (address see above)
A 1-cm length of the total fascicular area of the right sural nerve was sampled, and two thirds were paraffin-embedded and processed for the usual histological and immunohistochemical studies. The remainder was fixed in 2.5 % glutaraldehyde, embedded in epoxy resin, and selected 1%tin-thick sections were used for morphometry and electron microscope observation. Morphometric studies showed moderate loss of large and small myelinated fibers (density of the myelinated fibers, 4,778/mm;). Fiber density distribution obtained from the electron microscopic pictures indicated loss of unmyelinated fibers (density; 18,041/mm2). Atrophic, degenerative or dissolved axons surrounded by convoluted myelin, occasionally accompanied by loosened lamellae of the inner layers of myelin, were noted on both light and electron microscopy. The axonplasm of unmyelinated fibers was also degenerated or dissolved. Flattened tongues of Schwann cell processes were occasionally seen, along with dystrophic axons filled with mitochondria, vacuoles, vesicles or proliferated cisterns of smooth endoplasmic reticulum and some accumulation of glycogen granules in the axonplasm. Several clusters of small myelinated fibers and minor onion bulbs were also found. Small vessels in the endoneurium and the perineurium exhibited marked vascular wall thickening. In addition to this axonal and vascular pathology, a few Schwann ceils forming myelinated fibers possessed numerous distended cisterns of rER (Figs. 1-3) which were filled with the filaments of about 7-8 nm in diameter. Furthermore, some nuclei of the Schwann cells also exhibited large inclusion-like structures,
665
Fig. 1. Numerous cisterns are dilated and filled with filaments and a few membranous bodies in the cytoplasm of the Schwann cell. • 9,580
Fig. 2. The nucleus of the Schwann cell contains a large intranuclear inclusion composed of fine granular substances and electrondense globules. Numerous filament-filled cisterns are seen in the cytoplasm. The filaments appear thinner than neurofilaments in the axon (left side), x 9,570
which were composed of fine granular substances and electrondense materials accumulating between the inner and outer nuclear membranes (Figs. 2, 3). The staining properties or reactivities of these inclusions were studied by the following methods: hematoxylin-eosin, luxol fast blue-periodic acid Schiff, Congo red, and antibodies to actin, ubiquitin, cystatin C, neurofilament, glial fibrillary acidic protein, [3-tubulin, ct-tubulin, vimentin, tau, paired helical filaments, microtubule-associated proteins, desmin, ~protein, IgG, IgD, IgA, IgM, L chain, and • chain, Because of the limited number of these inclusions in a section, no definite reactive patterns were detected.
Discussion Several types of inclusions are well k n o w n to occur in the cisterns of the r E R of several types of cells. These include tubular aggregates and intracisternal tubules, microtubules, microtubuloreticular structures, proteinaceous granules, crystalline inclusions, and laminated inclusions [5]. Most of these inclusions consist of tubules m o r e than 30 nm in diameter, or microtubules f r o m 12 to 30 nm. O n the contrary, accumulations of filaments less than 12 n m in d i a m e t e r in the r E R are rare.Vallat et al. [13] r e p o r t e d an a b n o r m a l proliferation of microfilaments 8 - 9 n m in d i a m e t e r in a case of idiopathic sensory n e u r o p a t h y and in a case of Guillain-Barr6 syndrome and H o d g k i n ' s disease [7]. These ultrastructural features are practically identical to those of the present case. Both cases showed demyelinative changes in the peripheral nerves, whereas the present case showed axonal degeneration, p r o b a b l y due to long-standing diabetes mellitus and alcohol ingestion. In their cases, nearly half the myelinated Schwann cells were affected, whereas in the present case, only a few myelinated Schwann cells exhibited the filamentous accumulation. A n o t h e r patient, who was referred to by Vallat et al. [13], had similar accumulations in the r E R and perinuclear cistern
Fig. 3. High-power view of a section of Fig. 2 shows a intranuclear inclusion (upper left) surrounded by the inner nuclear membrane. The outer nuclear membrane is indicated by arrows. In the cytoplasm, dilated cisterns are studded with ribosomes and contain fine filaments, x 22,800
of leukemic lymphocytes [11]. T h e filaments of about 11 n m in d i a m e t e r showed striation, unlike those in the Schwann cell. Micro filaments of a b o u t 8 n m in d i a m e t e r are present in the cytoplasm of Schwann cells [1, 10]. Increased cytoplasmic microfilaments have b e e n r e p o r t e d in pathological conditions [2] such as rare cases with connatal p o l y n e u r o p a t h y [12], giant axonal n e u r o p a t h y [8] and oral nerve sheath m y x o m a [14]. In these states, microfilaments accumulated freely in the cytoplasm, not in the cisterns of the r E R . In addition to filamentous accumulations, perinuclear cisterns also showed deposition of granular m a t e rials. T h e ultrastructure looked similar to those of D u t c h e r ' s bodies [3, 4, 9] or intranuclear Russell bodies [5] in lymphocytes and plasmacytoid lymphocytes. These bodies develop in the perinuclear cisterns or
666 within the nucleus limited by a unit m e m b r a n e (an inner nuclear m e m b r a n e ) , and consist of granular materials and electron-dense substance that are derived f r o m immunoglobulins. I m m u n o g l o b u l i n s and other proteins in the inclusions were not detected in the present case. However, descriptions of similar intranuclear pseudoinclusions of the Schwann cell are not available, despite an extensive search of the literature. T h e granular materials might represent dissolved forms of microfilaments because of the continuity of the perinuclear cisterns with the r E R , where excessive microfilaments a p p e a r e d to be secreted or precipitated. T h e excessive production could represent s o m e reaction of the cisternal system of the Schwann cells to pathological changes of the nerve fibers. However, integral proteins of the cell, including microfilaments, are produced by free ribosomes or polysomes, not by r E R [6]. T h e chemical composition of the mircofilaments seen in the present case is not k n o w n and h o w they c o m e to lie in the r E R will require f u r t h e r study. Similar observations in other states involving the peripheral nerve m a y address these issues.
Acknowledgement.The authors thank Dr. Kouichi Okamoto, the Department of Neurology, Gumma University School of Medicine, Gumma for performing immunohistochemical studies.
References 1. Askanas V, Engel WK, Dalakas MC, Lawrence JV, Carter LS (1980) Human Schwann cells in tissue culture. Histochemical and ultrastruCtural studies. Arch Neurol 37:329-337
2. Bigbee JW,Yoshino JE, DeVries GH (1987) Morphological and proliferative responses of cultured Schwann cells following rapid phagocytosis of a myelin-enriched fraction. J Neurocytol 16: 487-496 3. Djaldetti M, Lewinski UH (1978) Origin of intranuclear inclusions in myeloma cells. Scand J Haematol 20:200-205 4. Dutcher TF, Fahey JL (1959) The histopathology of the macroglubulinemia of Waldenstrom. J Natl Cancer Inst 22: 887-917 5. Ghadially FN (1988) Ultrastructural pathology of the cell and matrix, vol 1, 3rd edn. Butterworth, London, pp 78-79; 413-571 6. Heywood SM, Dowben RM, Rich A (1967) The identification of polyribosomes synthesizing myosin. Proc Natl Acad Sci USA 57:1002-1009 7. Julien J, Vital C1, Aupy G, Laguency A, Darriet D, Brechenreacher C (1980) Guillain-Barr6 syndrome and Hodgkin's disease. Ultrastructural study of a peripheral nerve. J Neurol Sci 45: 23-27 8. Ouvrier RA (1989) Giant axonal neuropathy. A review. Brain Dev 11:207-214 9. Pappas CTE, Johnson PC, Sonntag VKH (t988) Signet-ring cell lymphoma of the central nervous system. J Neurosurg 69: 789-792 10. Raine CS (1984) Morphology of myelin and myelination. In: Morrell P (ed) Myelin. Plenum, New York, pp 1-50 11. Stefani S, Chandra S, Schrek R, Tonaki H, Knospe WH (1977) Endoplasmic reticulum-associated structures in lymphocytes from patients with chronic lymphocytic leukemia. Blood 50:125-139 12. Ulrich J, Hirt H-R, Kleihues E Oberholzer M (1981) Connatal polyneuropathy: a case with proliferated microfilaments in Schwann cells. Acta Neuropathol (Berl) 55:39-46 13. Vallat JM,Vital C, LeBoutet MJ, Loubet A, Brechenmacher C (1982) Abnormal proliferation of intraergastoplasmic microfilaments in myelinated Schwann cells. J Neuropathol Exp Neurol 41: 460-465 14. Yamamoto H, Kawana T (1988) Oral nerve sheath myxoma. Report of a case with findings of ultrastructural and immunohistochemical studies. Acta Pathol Jpn 38:121-127
Aaa HeuropathologKa (~) Springer-Verlag1992
Case reports Intracisternal inclusions in Schwann cells of the sural nerve Hirofumi Kusaka and Terukuni Imai Department of Neurology, Kitano Hospital and Neurological Center, 13-3, Kamiyama-cho, Kita-ku, Osaka 530, Japan Received October 31, 1991; Accepted December 23, 1991
Summary. Biopsy of the sural nerve in a 74-year-old man with chronic neuropathy demonstrated Schwann cells that possessed multiple cisterns of rough endoplasmic reticulum filled with 7- to 8-nm filaments and perinuclear cisterns that were markedly distended with fine granular substances and electron-dense globules. To our knowledge, this is the third case exhibiting filamentous inclusions in Schwann cells. Unlike the previous cases, however, this case showed inclusions in the distended perinuclear cisterns and axonal degeneration. The significance of these alterations remains to be elucidated. Key words: Dutcher's bodies - Endoplasmic reticulum -
to pain and touch in a glove and stocking distribution, and mild weakness of the lower extremities and hands. CSF examination revealed a total protein of 34 rag/100 ml and 4 cells/mm3. The following laboratory tests were normal or negative: plasma vitamin Ba, B6, B12, folate, TSH, thyroxine, RBC, hematocrit, Hb,WBC, BUN, serum creatinine, CPK, immunoglobulins, cryoglobulin, and M-protein. Even on treatment with acetohexamide, his fasting blood sugar was 180, and hemoglobin Ale was 8.9 (normal: 4.0 %-6.0 %) on admission. Electrophysiological studies showed mild slowing of maximal motor conduction velocity of the tibial and peroneal nerves and mild slowing of maximal sensory conduction velocity of the sural nerve with prolonged latencies. Needle electromyographic examination revealed evidence of spontaneous activity (fibrillations) and reduced recruitment patterns with maximal voluntary effort in several muscles of the lower extremities. A biopsy of the sural nerve was performed.
Microfilaments - Perinuclear cistern - Schwann cell
Neuropathological findings Vallat et al. [13] reported unprecedented filamentous accumulation in the rough endoplasmic reticulum (rER) of myelinated Schwann cells in two cases with peripheral neuropathy. There have been no further reports of similar inclusions in Schwann cells. We recently enocuntered a patient with chronic polyneuropathy, in whom were found several Schwann cells containing filamentous accumulations in the rER, as well as granular deposits in the perinuclear cisterns.
Case report The patient had a history of poorly controlled non-insulindependent diabetes mellitus since the age of 40. He underwent partial gastrectomy for peptic ulcer at age 63, and developed unsteadiness of gait and weakness of the lower extremities at age 71. The symptoms gradually progressed and he was referred to our hospital at age 74. He drank about 100 g of alcohol daily. There was no family history of neurological disorders. Neurological examination revealed areflexia of all four extremities, symmetric vibration sense deficit particularly in the lower extremities, mild hypesthesia Offprint requests to: H. Kusaka (address see above)
A 1-cm length of the total fascicular area of the right sural nerve was sampled, and two thirds were paraffin-embedded and processed for the usual histological and immunohistochemical studies. The remainder was fixed in 2.5 % glutaraldehyde, embedded in epoxy resin, and selected 1%tin-thick sections were used for morphometry and electron microscope observation. Morphometric studies showed moderate loss of large and small myelinated fibers (density of the myelinated fibers, 4,778/mm;). Fiber density distribution obtained from the electron microscopic pictures indicated loss of unmyelinated fibers (density; 18,041/mm2). Atrophic, degenerative or dissolved axons surrounded by convoluted myelin, occasionally accompanied by loosened lamellae of the inner layers of myelin, were noted on both light and electron microscopy. The axonplasm of unmyelinated fibers was also degenerated or dissolved. Flattened tongues of Schwann cell processes were occasionally seen, along with dystrophic axons filled with mitochondria, vacuoles, vesicles or proliferated cisterns of smooth endoplasmic reticulum and some accumulation of glycogen granules in the axonplasm. Several clusters of small myelinated fibers and minor onion bulbs were also found. Small vessels in the endoneurium and the perineurium exhibited marked vascular wall thickening. In addition to this axonal and vascular pathology, a few Schwann ceils forming myelinated fibers possessed numerous distended cisterns of rER (Figs. 1-3) which were filled with the filaments of about 7-8 nm in diameter. Furthermore, some nuclei of the Schwann cells also exhibited large inclusion-like structures,
665
Fig. 1. Numerous cisterns are dilated and filled with filaments and a few membranous bodies in the cytoplasm of the Schwann cell. • 9,580
Fig. 2. The nucleus of the Schwann cell contains a large intranuclear inclusion composed of fine granular substances and electrondense globules. Numerous filament-filled cisterns are seen in the cytoplasm. The filaments appear thinner than neurofilaments in the axon (left side), x 9,570
which were composed of fine granular substances and electrondense materials accumulating between the inner and outer nuclear membranes (Figs. 2, 3). The staining properties or reactivities of these inclusions were studied by the following methods: hematoxylin-eosin, luxol fast blue-periodic acid Schiff, Congo red, and antibodies to actin, ubiquitin, cystatin C, neurofilament, glial fibrillary acidic protein, [3-tubulin, ct-tubulin, vimentin, tau, paired helical filaments, microtubule-associated proteins, desmin, ~protein, IgG, IgD, IgA, IgM, L chain, and • chain, Because of the limited number of these inclusions in a section, no definite reactive patterns were detected.
Discussion Several types of inclusions are well k n o w n to occur in the cisterns of the r E R of several types of cells. These include tubular aggregates and intracisternal tubules, microtubules, microtubuloreticular structures, proteinaceous granules, crystalline inclusions, and laminated inclusions [5]. Most of these inclusions consist of tubules m o r e than 30 nm in diameter, or microtubules f r o m 12 to 30 nm. O n the contrary, accumulations of filaments less than 12 n m in d i a m e t e r in the r E R are rare.Vallat et al. [13] r e p o r t e d an a b n o r m a l proliferation of microfilaments 8 - 9 n m in d i a m e t e r in a case of idiopathic sensory n e u r o p a t h y and in a case of Guillain-Barr6 syndrome and H o d g k i n ' s disease [7]. These ultrastructural features are practically identical to those of the present case. Both cases showed demyelinative changes in the peripheral nerves, whereas the present case showed axonal degeneration, p r o b a b l y due to long-standing diabetes mellitus and alcohol ingestion. In their cases, nearly half the myelinated Schwann cells were affected, whereas in the present case, only a few myelinated Schwann cells exhibited the filamentous accumulation. A n o t h e r patient, who was referred to by Vallat et al. [13], had similar accumulations in the r E R and perinuclear cistern
Fig. 3. High-power view of a section of Fig. 2 shows a intranuclear inclusion (upper left) surrounded by the inner nuclear membrane. The outer nuclear membrane is indicated by arrows. In the cytoplasm, dilated cisterns are studded with ribosomes and contain fine filaments, x 22,800
of leukemic lymphocytes [11]. T h e filaments of about 11 n m in d i a m e t e r showed striation, unlike those in the Schwann cell. Micro filaments of a b o u t 8 n m in d i a m e t e r are present in the cytoplasm of Schwann cells [1, 10]. Increased cytoplasmic microfilaments have b e e n r e p o r t e d in pathological conditions [2] such as rare cases with connatal p o l y n e u r o p a t h y [12], giant axonal n e u r o p a t h y [8] and oral nerve sheath m y x o m a [14]. In these states, microfilaments accumulated freely in the cytoplasm, not in the cisterns of the r E R . In addition to filamentous accumulations, perinuclear cisterns also showed deposition of granular m a t e rials. T h e ultrastructure looked similar to those of D u t c h e r ' s bodies [3, 4, 9] or intranuclear Russell bodies [5] in lymphocytes and plasmacytoid lymphocytes. These bodies develop in the perinuclear cisterns or
666 within the nucleus limited by a unit m e m b r a n e (an inner nuclear m e m b r a n e ) , and consist of granular materials and electron-dense substance that are derived f r o m immunoglobulins. I m m u n o g l o b u l i n s and other proteins in the inclusions were not detected in the present case. However, descriptions of similar intranuclear pseudoinclusions of the Schwann cell are not available, despite an extensive search of the literature. T h e granular materials might represent dissolved forms of microfilaments because of the continuity of the perinuclear cisterns with the r E R , where excessive microfilaments a p p e a r e d to be secreted or precipitated. T h e excessive production could represent s o m e reaction of the cisternal system of the Schwann cells to pathological changes of the nerve fibers. However, integral proteins of the cell, including microfilaments, are produced by free ribosomes or polysomes, not by r E R [6]. T h e chemical composition of the mircofilaments seen in the present case is not k n o w n and h o w they c o m e to lie in the r E R will require f u r t h e r study. Similar observations in other states involving the peripheral nerve m a y address these issues.
Acknowledgement.The authors thank Dr. Kouichi Okamoto, the Department of Neurology, Gumma University School of Medicine, Gumma for performing immunohistochemical studies.
References 1. Askanas V, Engel WK, Dalakas MC, Lawrence JV, Carter LS (1980) Human Schwann cells in tissue culture. Histochemical and ultrastruCtural studies. Arch Neurol 37:329-337
2. Bigbee JW,Yoshino JE, DeVries GH (1987) Morphological and proliferative responses of cultured Schwann cells following rapid phagocytosis of a myelin-enriched fraction. J Neurocytol 16: 487-496 3. Djaldetti M, Lewinski UH (1978) Origin of intranuclear inclusions in myeloma cells. Scand J Haematol 20:200-205 4. Dutcher TF, Fahey JL (1959) The histopathology of the macroglubulinemia of Waldenstrom. J Natl Cancer Inst 22: 887-917 5. Ghadially FN (1988) Ultrastructural pathology of the cell and matrix, vol 1, 3rd edn. Butterworth, London, pp 78-79; 413-571 6. Heywood SM, Dowben RM, Rich A (1967) The identification of polyribosomes synthesizing myosin. Proc Natl Acad Sci USA 57:1002-1009 7. Julien J, Vital C1, Aupy G, Laguency A, Darriet D, Brechenreacher C (1980) Guillain-Barr6 syndrome and Hodgkin's disease. Ultrastructural study of a peripheral nerve. J Neurol Sci 45: 23-27 8. Ouvrier RA (1989) Giant axonal neuropathy. A review. Brain Dev 11:207-214 9. Pappas CTE, Johnson PC, Sonntag VKH (t988) Signet-ring cell lymphoma of the central nervous system. J Neurosurg 69: 789-792 10. Raine CS (1984) Morphology of myelin and myelination. In: Morrell P (ed) Myelin. Plenum, New York, pp 1-50 11. Stefani S, Chandra S, Schrek R, Tonaki H, Knospe WH (1977) Endoplasmic reticulum-associated structures in lymphocytes from patients with chronic lymphocytic leukemia. Blood 50:125-139 12. Ulrich J, Hirt H-R, Kleihues E Oberholzer M (1981) Connatal polyneuropathy: a case with proliferated microfilaments in Schwann cells. Acta Neuropathol (Berl) 55:39-46 13. Vallat JM,Vital C, LeBoutet MJ, Loubet A, Brechenmacher C (1982) Abnormal proliferation of intraergastoplasmic microfilaments in myelinated Schwann cells. J Neuropathol Exp Neurol 41: 460-465 14. Yamamoto H, Kawana T (1988) Oral nerve sheath myxoma. Report of a case with findings of ultrastructural and immunohistochemical studies. Acta Pathol Jpn 38:121-127
