Schwannoma with metastatic carcinoma of the breast: an unconventional form of glandular peripheral sheath tumor.
We report a schwannoma of the left arm harboring metastatic adenocarcinoma in a 68-year-old woman who had a history of invasive ductal carcinoma of the left breast with widespread metastases. The soft tissue tumor of the left arm had the morphological features of a typical schwannoma except for the presence of multiple foci of moderately to poorly differentiated adenocarcinoma and a grossly visible cyst that was lined by benign appearing cuboidal to low columnar epithelium. The immunohistochemical studies showed that the spindle cells were diffusely and strongly positive for vimentin, S-100 protein, and collagen type IV, and focally reactive for Leu 7. The cyst and the foci of adenocarcinoma were both stained for cytokeratin, but the adenocarcinomatous foci also were immunoreactive for estrogen receptor, gross cystic disease fluid protein, and focally for S-100 protein, in contrast to the lack of positivity for these three markers in the epithelium of the cyst. To the best of our knowledge this case is a unique one of a schwannoma with metastatic mammary carcinoma producing yet another variation on the theme of a glandular peripheral nerve sheath tumor.
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Lauren V. Ackerman Laboratory of Surgical Pathology, Barnes Hospital, Washington University Medical Center, St Louis, MO 63110, USA.
Dehner
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D000368:Aged; D001132:Arm; D001943:Breast Neoplasms / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000473:pathology* / Q000556:secondary; D003560:Cysts / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D009378:Neoplasms, Multiple Primary / Q000473:pathology*; D009442:Neurilemmoma / Q000473:pathology* / Q000556:secondary; D012983:Soft Tissue Neoplasms / Q000473:pathology*