Skeletal Radiol (1992) 21 : 343-345
Skeletal Radiology
Case report 742 Yoshinao Oda, M.D. ~, Hiroshi Hashimoto, M.D. 1, Masazumi Tsuneyoshi, M.D. 1, and Nobuhiko Ono, M.D. 2 Second Department of Pathology, Faculty of Medicine, Kyushu University, Higashi-ku 2 0 n o Hospital, Hakata-ku, Fukuoka, Japan
Radiological studies
Clinical information A 72-year-old man injured the dorsum of his left hand when it was struck by the pointed head of an umbrclla at the age of 68 years. Radiography at the time of injury showed no remarkable bony changes, including fracture. The wound healed without any surgical intervention leaving no symptoms of pain or infection. During the 4 months before the current admission, however, the patient complained a new of pain and swelling on his opisthenar. Plain film radiography at this time revealed a sharply demarcated, osteolytic, medullary lesion of the left fifth metacarpal bone. The cortex was thinned partially without interruption or permeation. No periosteal reaction or soft-tissue mass was present (Fig. 1). Curettage combined with grafting of iliac bone chips was carried out. Address reprint requests to: M. Tsuneyoshi,
Fig. 1. A Anteroposterior and B oblique views of the left hand show an irregular, osteolytic but well defined lesion in the left fifth metacarpal bone. The cortex is thin and without cortical expansion. No periosteal reaction or soft-tissue mass is present
M.D., Second Department of Pathology, Faculty of Medicine, Kyushu University, 31-1 Maidashi, Higashi-ku, Fukuoka 812, Japan
9 1992 International Skeletal Society
344
Diagnosis: Intraosseous epidermoid cyst arising in the fifth metacarpal bone
Y. Oda et al. : Case report 742
Pathological studies
The differential diagnosis inlcuded enchondroma or giant cell reparative granuloma of the small bones of the hands and feet.
Discussion Surgical exploration of the lesion from a dorsal approach demonstrated a slightly expanding cortex without any soft-tissue mass. The dorsal cortex of the fifth metacarpal was partially defective over an area of 2.0x0.5 cm, with a cystic cavity filled by a whitish-yellow caseous substance in the medulla. Microscopically, the cyst was lined by a thick keratinizing squamous epithelium, containing laminated keratin, while the fibrous wall showed a foreign body giant cell reaction (Fig. 2). An intraosseous epidermoid cyst is an uncommon cystic lesion of bone. Such a cyst has been previously reported to occur in the jaw and skull or in the phalanges. In 1953, Carroll introduced his own 6 cases and 18 previously reported cases of epidermold cyst affecting the terminal phalanx of the hand [1]. Over 95% of the cysts in the digital bones affect the distal tuft of the terminal phalanx [7], although a few have been observed either in a toe [11, 12] or in the traumatically amputated residual end of a finger [12]. Rare sites of epidermoid cysts have been reported in the tibia [2], ulna [8], femur [5], and sternum [6]. It is perhaps surprising that there have been no previous case reports of intraosseous epidermoid cysts arising in a metacarpal bone. Authors reporting a large series (t 1-84 cases) of epidermoid cysts in the phalanges have explained that the phalangeal epidermoid cyst results from an implantation of the epidermis caused by either trauma or operation [1, 3, 11, 12]. In fact, the current case had a history of a penetrating injury in the opisthenar. Most of the epidermoid cysts occurring in a terminal phalanx are sharply demarcated with single, osteolytic defects comprising their radiological features [7]. A radiological
Fig. 2. A Photomicrograph of the lesion demonstrates a typical appearance of the cyst lined by stratified squamous epithelium ( x 55) B A foreign body giant cell reaction has been caused by the rupture of the epidermoid cyst (upper) into the surrounding soft tissue; chronic inflammation is associated ( x 230)
Y. Oda et al. : Case report 742 distinction between epidermoid cyst and e n c h o n d r o m a is n o t clear. Enc h o n d r o m a s occur m o r e c o m m o n l y in the proximal than in the distal p h a l a n x (where an epidermoid cyst usually arises) and radiologically often show spotty calcification. For this reason, surgeons m a y originally diagnose this lesion as an e n c h o n d r o m a rather t h a n as an epidermoid cyst when it occurs m o r e proximally in a digit. Lerner and Southwick in 1968 reported a case o f a phalangeal epidermoid cyst arising 6 m o n t h s after the removal o f an e n c h o n d r o m a at the same site [3]. G i a n t cell reparative g r a n u l o m a o f the h a n d s and feet mainly occurs in the second and third decades o f life [4, 9]. The radiological appearance is that o f a radiolucent lesion expanding the b o n e [4, 13]. Histologically, the contents o f an epidermoid cyst m a y rupture into the s u r r o u n d ing fibrous tissue s t r o m a a n d elicit an intense i n f l a m m a t o r y and foreign b o d y reaction in the liberated keratin. The resulting a c c u m u l a t i o n o f giant cells m a y at first suggest a diagnosis o f a giant cell t u m o r or giant cell reparative g r a n u l o m a [10]. Schajowicz et al. stated that intraosseous epidermoid cysts did n o t seem to be
345 as rare as previously p r e s u m e d f r o m the small n u m b e r o f published cases. This a p p a r e n t rarity m a y be due to either diagnostic error or to the fact that m a n y isolated cases have actually n o t been reported [12]. In summary, a case o f intraosseous epidermoid cyst arising in a metacarpal b o n e in 72-year-old m a n has been reported. In the current case the patient gave a history o f trauma. T h e lesion arose in the metacarpal, but n o t in the phalanx. The unusual location o f the lesion presented diagnostic problems in respect to its radiological differentiation f r o m enc h o n d r o m a or other benign b o n e lesions.
Acknowledgement. We thank Emeritus Prof. M. Enjoji, Faculty of Medicine, Kyushu University, for his helpful comments on this manuscript.
References 1. Carroll RE (1953) Epidermoid (epithelial) cyst of the hand skeleton. Am J Surg 85 : 327 2. Exner G, Hort W, B6ger A (1978) Epidermoidzyste der tibia. Z Orthop 116:362 3. Lerner MR, Southwick WO (1968) Keratin cysts in phalangeal bones. Report of an unusual case. J Bone Joint Surg [Am] 50:365
4. Lorenzo JC, Dorfman HD (1980) Giantcell reparative granuloma of short tubular bones of hands and feet. Am J Surg Pathol 4:551 5. Maritz NGJ, De Bruin B (1980) Epidermoid cysts of the femur. A case report. S Air Med J 58 : 779 6. Mirra JM (1980) Bone tumors. Diagnosis, treatment. JB Lippincott, Philadelphia, p 438 7. Mirra JM, Picci P, Gold RH (1989) Bone tumors, vol 2. Lea & Febiger, Philadelphia, p 1263 8. Mollan RAB, Wray AR, Hayes D (1982) Traumatic epidermoid cyst of the ulna. Report of a case. J Bone Joint Surg [Br] 64: 456 9. Picci P, Baldini N, Sudanese A, Boriani S, Campanacci M (1986) Giant cell reparative granuloma and other giant cell lesions of the bones of the hands and feet. Skeletal Radiol 15 : 415 10. Resnick D, Niwayama G (1988) Diagnosis of bone and joint disorders, 2nd edn. WB Saunders, Philadelphia, p 3831 11. Roth SI (1964) Squamous cysts involving the skui1 and distal phalanges. J Bone Joint Surg [Am] 46:1442 12. Schajowicz F, Aielio CL, Stullitel I (1970) Cystic and pseudocystic lesions of the terminal phalanx with special reference to epidermoid cyst. Clin Orthop 68 : 84 13. Wold LE, Dobyns JH, Swee RG, Dahlin DC (1986) Giant cell reaction (giant cell reparative granuloma) of the small bones of the hands and feet. Am J Surg Pathol 10:491
Skeletal Radiology
Case report 742 Yoshinao Oda, M.D. ~, Hiroshi Hashimoto, M.D. 1, Masazumi Tsuneyoshi, M.D. 1, and Nobuhiko Ono, M.D. 2 Second Department of Pathology, Faculty of Medicine, Kyushu University, Higashi-ku 2 0 n o Hospital, Hakata-ku, Fukuoka, Japan
Radiological studies
Clinical information A 72-year-old man injured the dorsum of his left hand when it was struck by the pointed head of an umbrclla at the age of 68 years. Radiography at the time of injury showed no remarkable bony changes, including fracture. The wound healed without any surgical intervention leaving no symptoms of pain or infection. During the 4 months before the current admission, however, the patient complained a new of pain and swelling on his opisthenar. Plain film radiography at this time revealed a sharply demarcated, osteolytic, medullary lesion of the left fifth metacarpal bone. The cortex was thinned partially without interruption or permeation. No periosteal reaction or soft-tissue mass was present (Fig. 1). Curettage combined with grafting of iliac bone chips was carried out. Address reprint requests to: M. Tsuneyoshi,
Fig. 1. A Anteroposterior and B oblique views of the left hand show an irregular, osteolytic but well defined lesion in the left fifth metacarpal bone. The cortex is thin and without cortical expansion. No periosteal reaction or soft-tissue mass is present
M.D., Second Department of Pathology, Faculty of Medicine, Kyushu University, 31-1 Maidashi, Higashi-ku, Fukuoka 812, Japan
9 1992 International Skeletal Society
344
Diagnosis: Intraosseous epidermoid cyst arising in the fifth metacarpal bone
Y. Oda et al. : Case report 742
Pathological studies
The differential diagnosis inlcuded enchondroma or giant cell reparative granuloma of the small bones of the hands and feet.
Discussion Surgical exploration of the lesion from a dorsal approach demonstrated a slightly expanding cortex without any soft-tissue mass. The dorsal cortex of the fifth metacarpal was partially defective over an area of 2.0x0.5 cm, with a cystic cavity filled by a whitish-yellow caseous substance in the medulla. Microscopically, the cyst was lined by a thick keratinizing squamous epithelium, containing laminated keratin, while the fibrous wall showed a foreign body giant cell reaction (Fig. 2). An intraosseous epidermoid cyst is an uncommon cystic lesion of bone. Such a cyst has been previously reported to occur in the jaw and skull or in the phalanges. In 1953, Carroll introduced his own 6 cases and 18 previously reported cases of epidermold cyst affecting the terminal phalanx of the hand [1]. Over 95% of the cysts in the digital bones affect the distal tuft of the terminal phalanx [7], although a few have been observed either in a toe [11, 12] or in the traumatically amputated residual end of a finger [12]. Rare sites of epidermoid cysts have been reported in the tibia [2], ulna [8], femur [5], and sternum [6]. It is perhaps surprising that there have been no previous case reports of intraosseous epidermoid cysts arising in a metacarpal bone. Authors reporting a large series (t 1-84 cases) of epidermoid cysts in the phalanges have explained that the phalangeal epidermoid cyst results from an implantation of the epidermis caused by either trauma or operation [1, 3, 11, 12]. In fact, the current case had a history of a penetrating injury in the opisthenar. Most of the epidermoid cysts occurring in a terminal phalanx are sharply demarcated with single, osteolytic defects comprising their radiological features [7]. A radiological
Fig. 2. A Photomicrograph of the lesion demonstrates a typical appearance of the cyst lined by stratified squamous epithelium ( x 55) B A foreign body giant cell reaction has been caused by the rupture of the epidermoid cyst (upper) into the surrounding soft tissue; chronic inflammation is associated ( x 230)
Y. Oda et al. : Case report 742 distinction between epidermoid cyst and e n c h o n d r o m a is n o t clear. Enc h o n d r o m a s occur m o r e c o m m o n l y in the proximal than in the distal p h a l a n x (where an epidermoid cyst usually arises) and radiologically often show spotty calcification. For this reason, surgeons m a y originally diagnose this lesion as an e n c h o n d r o m a rather t h a n as an epidermoid cyst when it occurs m o r e proximally in a digit. Lerner and Southwick in 1968 reported a case o f a phalangeal epidermoid cyst arising 6 m o n t h s after the removal o f an e n c h o n d r o m a at the same site [3]. G i a n t cell reparative g r a n u l o m a o f the h a n d s and feet mainly occurs in the second and third decades o f life [4, 9]. The radiological appearance is that o f a radiolucent lesion expanding the b o n e [4, 13]. Histologically, the contents o f an epidermoid cyst m a y rupture into the s u r r o u n d ing fibrous tissue s t r o m a a n d elicit an intense i n f l a m m a t o r y and foreign b o d y reaction in the liberated keratin. The resulting a c c u m u l a t i o n o f giant cells m a y at first suggest a diagnosis o f a giant cell t u m o r or giant cell reparative g r a n u l o m a [10]. Schajowicz et al. stated that intraosseous epidermoid cysts did n o t seem to be
345 as rare as previously p r e s u m e d f r o m the small n u m b e r o f published cases. This a p p a r e n t rarity m a y be due to either diagnostic error or to the fact that m a n y isolated cases have actually n o t been reported [12]. In summary, a case o f intraosseous epidermoid cyst arising in a metacarpal b o n e in 72-year-old m a n has been reported. In the current case the patient gave a history o f trauma. T h e lesion arose in the metacarpal, but n o t in the phalanx. The unusual location o f the lesion presented diagnostic problems in respect to its radiological differentiation f r o m enc h o n d r o m a or other benign b o n e lesions.
Acknowledgement. We thank Emeritus Prof. M. Enjoji, Faculty of Medicine, Kyushu University, for his helpful comments on this manuscript.
References 1. Carroll RE (1953) Epidermoid (epithelial) cyst of the hand skeleton. Am J Surg 85 : 327 2. Exner G, Hort W, B6ger A (1978) Epidermoidzyste der tibia. Z Orthop 116:362 3. Lerner MR, Southwick WO (1968) Keratin cysts in phalangeal bones. Report of an unusual case. J Bone Joint Surg [Am] 50:365
4. Lorenzo JC, Dorfman HD (1980) Giantcell reparative granuloma of short tubular bones of hands and feet. Am J Surg Pathol 4:551 5. Maritz NGJ, De Bruin B (1980) Epidermoid cysts of the femur. A case report. S Air Med J 58 : 779 6. Mirra JM (1980) Bone tumors. Diagnosis, treatment. JB Lippincott, Philadelphia, p 438 7. Mirra JM, Picci P, Gold RH (1989) Bone tumors, vol 2. Lea & Febiger, Philadelphia, p 1263 8. Mollan RAB, Wray AR, Hayes D (1982) Traumatic epidermoid cyst of the ulna. Report of a case. J Bone Joint Surg [Br] 64: 456 9. Picci P, Baldini N, Sudanese A, Boriani S, Campanacci M (1986) Giant cell reparative granuloma and other giant cell lesions of the bones of the hands and feet. Skeletal Radiol 15 : 415 10. Resnick D, Niwayama G (1988) Diagnosis of bone and joint disorders, 2nd edn. WB Saunders, Philadelphia, p 3831 11. Roth SI (1964) Squamous cysts involving the skui1 and distal phalanges. J Bone Joint Surg [Am] 46:1442 12. Schajowicz F, Aielio CL, Stullitel I (1970) Cystic and pseudocystic lesions of the terminal phalanx with special reference to epidermoid cyst. Clin Orthop 68 : 84 13. Wold LE, Dobyns JH, Swee RG, Dahlin DC (1986) Giant cell reaction (giant cell reparative granuloma) of the small bones of the hands and feet. Am J Surg Pathol 10:491
