Sarcoma metastases to the skin: a clinicopathologic study of 65 patients

Sarcoma metastases to the skin are relatively rare, because most involve the lung, liver, or deep soft tissues. The authors of this report examined the distribution and clinical significance of cutaneous and superficial subcutaneous sarcoma metastases.

Sixty-five patients with histologically confirmed dermal and superficial subcutaneous sarcoma metastases were identified in pathology files from more than 25,000 patients with sarcoma who were evaluated at The University of Texas M. D. Anderson Cancer Center from 1989 to 2009. Pathology slides and clinical and radiological information were evaluated.

Cutaneous metastases were documented histologically in <0.25% of patients. The mean patient age was 49 years (range, 16-79 years), and there was an equivalent ratio of men to women. The most common source of metastasis was leiomyosarcoma (28 of 65 patients; 43%). The most common region of first skin metastasis was head and neck (33 patients; 51%), and the scalp predominated (25 patients; 38%). The mean time from primary tumor diagnosis to skin metastasis was 48 months (range, 0-166 months). Fifty-three patients (81%) had multiple metastases (skin and other). Among the patients who had complete clinical information available, 31 patients (62%) had other metastases diagnosed before skin involvement, 17 patients (34%) had skin metastases diagnosed first, and 2 patients (4%) had simultaneous presentation. The following clinical outcomes were documented: Twenty-nine patients (45%) died of disease, 24 patients (37%) remained alive with disease, and 12 patients were lost to follow-up. The mean time to death was 80 months (range, 9-224 months) after primary diagnosis, 45 months (range, 5-94 months) after the first metastasis to any site, and 27 months (range, 5-65 months) after the first skin metastasis.

Sarcoma metastases to the skin are rare. In this large study, leiomyosarcoma was the most common source, and the scalp was the most frequent site. The majority of patient with skin metastases harbored metastases elsewhere. However, skin was the initial site of metastasis in approximately 1 in 3 patients. Thus, clinical correlation is needed before establishing a diagnosis of primary cutaneous sarcoma, particularly leiomyosarcoma of scalp. Finally, the current results indicated that skin metastasis usually is a late event in sarcoma clinical progression and heralds a poor prognosis.