Email updates

Keep up to date with the latest news and content from BMC Cancer and BioMed Central.

Open Access Case report

A rare case of primary clear cell sarcoma of the pubic bone resembling small round cell tumor: an unusual morphological variant

Shoko Nakayama1*, Taiji Yokote1, Kazuki Iwaki1, Toshikazu Akioka1, Takuji Miyoshi1, Yuji Hirata1, Ayami Takayama1, Uta Nishiwaki1, Yuki Masuda1, Motomu Tsuji2 and Toshiaki Hanafusa1

Author affiliations

1 Department of Internal Medicine (I), Osaka Medical College, 2-7 Daigakumachi, Takatsuki City, Osaka, 569-0801, Japan

2 Division of Surgical Pathology, Osaka Medical College, 2-7 Daigakumachi, Takatsuki City, Osaka, 569-0801, Japan

For all author emails, please log on.

Citation and License

BMC Cancer 2012, 12:538  doi:10.1186/1471-2407-12-538

Published: 21 November 2012

Abstract

Background

Clear cell sarcoma (CCS) and malignant melanoma share overlapping immunohistochemistry with regard to the melanocytic markers HMB45, S100, and Melan-A. However, the translocation t(12; 22)(q13; q12) is specific to CCS. Therefore, although these neoplasms are closely related, they are now considered to be distinct entities. However, the translocation is apparently detectable only in 50%–70% of CCS cases. Therefore, the absence of a detectable EWS/AFT1 rearrangement may occasionally lead to erroneous exclusion of a translocation-negative CCS. Therefore, histological assessment is essential for the correct diagnosis of CCS. Primary CCS of the bone is exceedingly rare. Only a few cases of primary CCS arising in the ulna, metatarsals, ribs, radius, sacrum, and humerus have been reported, and primary CCS arising in the pubic bone has not been reported till date.

Case presentation

We present the case of an 81-year-old man with primary CCS of the pubic bone. Histological examination of the pubic bone revealed monomorphic small-sized cells arranged predominantly as a diffuse sheet with round, hyperchromatic nuclei and inconspicuous nucleoli. The cells had scant cytoplasm, and the biopsy findings indicated small round cell tumor (SRCT). Immunohistochemical staining revealed the tumor cells to be positive for HMB45, S100, and Melan-A but negative for cytokeratin (AE1/AE3) and epithelial membrane antigen. To the best of our knowledge, this is the first case report of primary CCS of the pubic bone resembling SRCT. This ambiguous appearance underscores the difficulties encountered during the histological diagnosis of this rare variant of CCS.

Conclusion

Awareness of primary CCS of the bone is clinically important for accurate diagnosis and management when the tumor is located in unusual locations such as the pubic bone and when the translocation t(12; 22)(q13; q12) is absent.

Keywords:
Clear cell sarcoma; Small round cell tumor; Pubic bone; Immunohistochemistry