Epithelioid angiomyolipoma (AML) is a newly established variant of AML, characterized by monomorphous epithelioid cells that show HMB-45 immunopositivity, and it often displays aggressive behavior. To date, they have mostly appeared in the kidneys; however, the present autopsy case of a 43-year-old female without the stigmata of tuberous sclerosis complex had a huge retroperitoneal mass, accompanied by involvement of the regional lymph nodes. Histopathologically, the tumor was composed of round, polygonal or short spindle-shaped monomorphous cells with abundant eosinophilic cytoplasm and large nuclei with frequent multinucleation. Mitotic figures were scattered. Mature fat cells and thick-walled abnormal blood vessels were totally absent. Immunohistochemically, the tumor cells were reactive with HMB-45 and alpha-smooth muscle actin antibodies. In spite of curative surgery and repeated radio- and chemotherapy, the tumor continued to grow and brought about the patient's death 4 years after the initial symptoms. At autopsy, the peritoneal cavity was filled with the tumor mass exceeding 5.5 kg. Histopathological features were essentially the same as those of biopsy samples, but the cellular pleomorphism and emperipolesis were more easily identified. This report calls attention to this unusual manifestation of AML in the retroperitoneum and the importance of distinguishing it from sarcomas and/or paragangliomas.
A report of an unusual esophageal tumor in an 81-year-old man is presented. The primary tumor was diagnosed as undifferentiated carcinoma at biopsy and had disappeared after irradiation treatment. However, multiple metastases were noted in the brain, lungs, kidneys, adrenals and spleen at autopsy. Histologically, metastases showed marked cartilaginous metaplasia as demonstrated by light microscopy, histochemical and immunohistochemical studies, although the initial biopsy sample did not possess chondroid matrix. Furthermore, an apparent transition could be traced from carcinomatous to chondroid cells, suggesting that the chondroid cells were derived from carcinoma cells. The carcinomatous area partially showed both squamous and glandular differentiation, although they were poorly differentiated. A retrospective immunohistochemical study that used a panel of antibodies suggested a phenotypic relevance between primary and metastatic tumors.
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