METASTATlC DISEASE TO THE SOFT TISSUES

Damron TA, Heiner JP, Aronowitz J (State University of New York Health Science Center, Syracuse NY 13202)

Introduction: Metastatic disease to the soft tissues has been reported rarely and most commonly in the form of case reports. The purpose of this report is to present the largest single series of patients with soft tissue metastases.

Methods: Twenty-one patients with soft tissue metastases comprise the study population and were reviewed retrospectively with respect to demographics, treatment, and outcome. Soft tissue metastases were defined as subcutaneous or muscular sites of metastatic neoplasms discretely separate from the primary site and nodal tissue not directly in the typical route of lymphatic drainage for the primary.

Results: Age for the twelve women and nine men ranged from 36 to 86 (mean 59) years. Underlying diagnosis was metastatic carcinoma (n =16), sarcoma (n=2), lymphoma (n=l), melanoma (1), and myeloma (n= 1), Primary carcinomas included lung (n= l 0), unknown primary (n=4), thyroid (n= 1), and bladder (n=l ). Sites of involvement included muscle (n=14), subcutaneous tissue (n=6), and inguinal nodal tissue (n=1 lung carcinoma). Muscle sites included thigh (n=4), brachialis (n=3), paravertebral (n=2), gastrosoleus (n=2), psoas, hip abductors, and pectorals. Subcutaneous sites included the thigh (n=2), chest wall (n=2), scalp and shoulder. The presenting symptom was a painful soft tissue mass in twelve, a painless soft tissue mass in seven, and pain alone in two (cervical paraspinous and psoas) patients. In thirteen cases, the soft tissue metastasis was the presenting symptom of previously unrecognized malignancy. In an additional two cases, the soft tissue metastasis was an isolated site of metastatic disease found concurrent with the primary disease. In three cases, the soft tissue metastasis was an isolated finding in patients in whom malignancy had been diagnosed four to six months previously. In only three patients did the soft tissue metastasis occur in the presence of disseminated metastatic disease. Treatment included chemotherapy in six patients (lymphoma, myeloma, osteosarcoma, melanoma, 2 lung carcinomas), local radiotherapy in sixteen patients, and surgical excision in four patients (osteosarcoma, myeloma, bladder and lung carcinoma). At follow-up six patients remained alive with disease (mean 9.7 months) and fifteen patients had died of disease (mean 5.5 months).

Conclusions: This report represents the largest single series of soft tissue metastases reported in the literature and underscores lung carcinoma as the most common primary. Metastatic disease should be included in the differential diagnosis of an isolated soft tissue mass. Metastatic carcinoma to the soft tissues has a very poor prognosis, with few patients in our series living more than one year.