The epithelioid fleshy tumor is a unique and rare neoplasm with an unclear tissue origin, first reported by Enzinger in 1970.

bubble_chart Pathological Changes

1. Gross findings: Superficial tumors visible to the naked eye, ranging from 1 to several centimeters in size. Deep-seated tumors may adhere to fascia or tendons, with a cross-section showing grayish-white areas alternating with hemorrhage and necrosis.

2. Microscopic findings: The main feature is the nodular arrangement of epithelioid tumor cells, with central degeneration and necrosis within the nodules. The tumor cells are polygonal, spindle-shaped (obesity), or large round, with deeply eosinophilic or lightly stained cytoplasm. The nuclei are round, with variable staining intensity, and may also appear vesicular. They often exhibit grade I to grade II pleomorphism.

bubble_chart Clinical Manifestations

It commonly occurs in individuals aged 20 to 40, often appearing on the extremities, with literature reporting half of cases involving the hands. The initial finding is typically a painless subcutaneous nodule about 1 cm in diameter, which ulcerates after 2 to 3 months. The ulcer then gradually infiltrates deeper, spreading along fascial membranes, tendons, and nerves.

bubble_chart Diagnosis

The diagnosis of this disease is based on three main features: the presence of epithelioid cells producing argentaffin fibers, the formation of numerous epithelioid cell nodules surrounded by collagen fibers, and central degeneration or necrosis within the nodules.

bubble_chart Treatment Measures

The local recurrence rate of this tumor is high, with reports reaching 80%. Additionally, there is a 10–30% metastasis rate to the draining lymph nodes. Therefore, wide local excision is recommended, along with consideration of draining lymph node dissection.

This tumor grows slowly, with a 10-year postoperative survival rate of 50%. There are also literature reports of patients surviving with lung metastasis occurring 23 years after surgery.