Challenging epithelioid mesenchymal neoplasms: mimics and traps

A Case of Pseudomyogenic Hemangioendothelioma of the Lower Extremity

Pseudomyogenic hemangioendothelioma (PMH) is a rare vascular tumor and was recently recognized as a distinct entity. It has a predilection for young male adults and it frequently occurs in distal extremities. Although it is known to follow an indolent course, multi-focal presentation and local recurrence are common. PMH should be differentiated from epithelioid sarcoma, epithelioid hemangioendothelioma, dermatofibrosarcoma protuberans, and rhabdomyosarcoma. Its characteristic immunohistochemical staining pattern and recurrent translocation t(7:19)(q22:q13) are the basis for its diagnosis. Surgical excision is the mainstay treatment, although chemotherapy can be considered in non-operable patients. We present a rare case of a 40-year-old Korean male patient diagnosed with PMH through an excisional biopsy to facilitate the recognition PMH in the clinical practice.

[Lymph node metastasis of osteosarcomas]

Lymph node metastasis of osteosarcomas is a rather rare phenomenon; according to different authors, the incidence of lymph node metastasis is 4 to 11%. The detection of lymph node metastases in osteosarcoma is associated with a significant reduction in the 5-year survival of patients and allows its classification as clinical stage IV tumor. The risk factors for lymph node metastases in patients with bone sarcomas are age (≥64 years), gender (female), nosological entity (undifferentiated pleomorphic sarcoma, osteosarcoma, chondrosarcoma), tumor depth (muscle, bone), and the size of primary tumor (>5 сm). The mechanism of lymph node metastasis of osteosarcomas seems to be related to mesenchymal-to-epithelial transition.