RESUMO
The histological predominance of one component in a germ cell tumor can lead to a mistaken diagnosis. Here, we describe a mediastinal teratoma with predominant vascular proliferation (90%) which on fi ne needle biopsy was diagnosed as a pulmonary hemangioma. Later, resection specimen revealed other components constituting ~4%, changing the diagnosis while illustrating theimportance of careful evaluation. A 37-year-old Caucasian male with shortness of breath, weight loss, and history of recently resolved pneumonia was diagnosed with hemangioma, after acomputed tomography guided fi ne needle biopsy of a -16.3-cm mediastinal pulmonary mass revealed abundant benign vascular elements. Following tumor excision, ~94% of the sample exhibited predominant vascular elementsThe mass also exhibited rare focal areas of malignant epithelium in a reticular arrangement and undifferentiated pleomorphic cells associated with vascular invasion. These atypical epithelial cells were positive for CD30, pan CK, AFP, -HCG and CD 117, thusprocuring a diagnosis of mediastinal mixed germ cell tumor. Although mixed germ cell tumors consist of various tissue types, diagnosis can be easily overlooked if one component dominates. Therefore, obtaining adequate representative neoplasm samples, and sectioning the samples thoroughly, searching for coexisting tissue types is critical for accurate diagnosis.
RESUMO
Plexiform fibrohistiocytic tumor is an uncommon mesenchymal tumor that can cause difficulty in diagnosis and surgical management. On clinical and histologic examination, these tumors can potentially be misdiagnosed as sebaceous/epidermal cysts. We report a case of plexiform fibrohistiocytic tumor in a young female, which on initial clinical evaluation was diagnosed as sebaceous cyst. The tumor was deeply invasive, with positive margins on two excisional biopsy specimens. The importance of recognition of this entity, potential pitfalls and prognosis are discussed and the literature is reviewed.