Epithelioid hemangioendothelioma is an uncommon malignant vascular tumor of intermediate grade that occurs in a variety of organs and soft tissues. Diagnosis of epithelioid hemangioendothelioma is often complicated by the rarity of the tumor, and because the tumor shares many morphologic features with other peritoneal neoplasms. This report presents 3 cases of epithelioid hemangioendotheliomas arising as primary tumors of the peritoneum and reviews 7 previously reported cases to establish the demographic, clinical, morphologic, immunohistochemical, and ultrastructural features of this neoplasm. These cases demonstrate that the light microscopic features are very similar to epithelioid hemangioendothelioma arising at more conventional sites, such as the liver, that immunohistochemical analysis provides a reliable approach for confirming or establishing the diagnosis, and that at least one endothelial marker (either CD31, CD34, or factor VIII) should be positive for a definitive diagnosis. This series identifies the characteristics of peritoneal epithelioid hemangioendothelioma that can be reliably used for diagnosis.

We report the features in fine-needle aspiration biopsy (FNAB) of thymic basaloid carcinomas. This is a rare neoplasm, of which there are only three documented in our hospital files. To the best of our knowledge, this is the first fine-needle aspiration (FNA) report on basaloid carcinoma of the thymus. This is a tumor in which the FNA diagnosis is difficult and the differential diagnosis is broad. We describe the cytologic features encountered in the three cases, and immunohistochemical and ultrastructural findings so as to raise awareness of this entity in the differential diagnosis of thymic neoplasms on FNABs. The cases studied included three male patients, aged 73, 65, and 50, who presented with anterior mediastinal masses, with no primary tumor elsewhere. FNAB was performed on two cases, followed by thymectomy. One case, additionally, had metastasis to a cervical lymph node, and the other two were associated with thymic cysts. The diagnoses on all three cases were thymic basaloid carcinoma.

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A case of diffuse-type tenosynovial giant cell tumor arising in the left upper extremity is reported in a 23-year-old man with neurofibromatosis type 1 (NF1)-Noonan syndrome. The predominately mononuclear cellular proliferation with psammomatous calcifications had the immunohistochemical and ultrastructural features of a fibrohistiocytic neoplasm. This uncommon type of soft tissue neoplasm occurring in this unique clinical setting served to open an inquiry into the subject of non-neurogenic tumors in association with NF1 and Noonan syndrome, both manifested in our patient. Nonossifying fibroma of bone as a presumptive fibrohistiocytic tumor is an uncommon but well-documented manifestation in NF1, whereas in Noonan-like syndrome, both giant cell granuloma and pigmented villonodular synovitis are recognized as associated lesions with histologic and immunophenotypic similarities with the diffuse-type tenosynovial giant cell tumor.