Doppler color flow findings in malignant fibrous histiocytoma of the scrotum and perineum

Abstract

Malignant fibrous histiocytoma (MFH) is a predominantly pleomorphic sarcoma that arises in the deep, soft tissues of the extremities and, in about 16% of cases, in the retroperitoneum.' It is the most common soft-tissue sarcoma of late adult life, accounting for approximately 10% of all sarcomas but only 1% of all malignancies.2 The classic histologic features include spindle (fibroblastlike) and rounded (histiocytic-like) cells arranged in storiform patterns accompanied by pleomorphic giant cells and inflammatory cells. The stroma may demonstrate myxoid components.' Any involvement of the inguinal region appears to be extremely rare, with only 2 cases involving the paratesticuladinguinal region2 and 12 cases involving the spermatic cord appearing in the lite r a t~r e .~We report an unusual case of malignant fibrous histiocytoma in a young man, arising in the deep subcutis layer of the left scrotum and involving the adjacent perineum. Examination with color flow doppler ultrasound showed tumor neovascularity and a low impedance flow characteristic. CASE REPORTA 24-year-old Hispanic man presented to surgical clinic with a 1-month history of a rapidly enlarging, firm mass behind the left testicle near the perineo-scrota1 junction. Real-time ultrasound examination utilizing a 7.5-MHz linear array/ color doppler transducer (Diasonics Spectra; Milpitas, California) demonstrated a 3.7 cm x 2.8 cm x 2.9 cm echogenic, solid, vascular mass adjacent 556to the left testicle and within the scrotum near the perineo-scrota1 junction (Figure 1). Spectral doppler waveform analysis demonstrated lowresistance type tumor neovascularity; average pulsatility index (PI) = 0.68 (Figure 2). A subsequent CT scan of the abdomen and pelvis demonstrated no evidence of metastatic disease.Two weeks later, the patient was admitted to the hospital for a left inguinal exploration and excision of the perineo-scrota1 mass. At surgery the mass measured 4.5 cm in diameter, having increased in size by more than 50% during the 2-week interval. Examination of surgical specimen revealed spindle cells in storiform whirls with high-grade mitotic activity and a variable amount of myxoid extracellular matrix. The tumor was poorly circumscribed and focal microscopic invasion of the surgical margins was evident.Subsequently, the patient was readmitted for a radical perineal resection, left orchiectomy and left scrotectomy. Examination of the re-excision specimen revealed clear surgical margins. Once again, the microscopic findings were consistent with a high-grade sarcoma such as malignant fibrous histiocytoma or rhabdomyosarcoma. Immunohistochemical staining, however, revealed a diffuse positive reaction t o alpha-1-antitrypsin antibodies, suggesting a fibrous histiocytic origin. The patient's postoperative course was uneventful, and he was started on a 6-week course of outpatient radiation therapy (6,000 cGy delivered to the perineum with special precautions for shielding of the right testicle); chemotherapy was also planned. DISCUSSIONConventional gray-s...