A nonrandom association of sarcoidosis in patients with gastrointestinal stromal tumor and other sarcomas.

Abstract

e22521 Background: Sarcoidosis can mimic metastatic cancer. Although sarcoidosis is associated with carcinomas, there are limited data supporting its association with GIST and other sarcomas. Prior reports on cancer related sarcoidosis are inconsistent in terms of prognosis; while some reports link sarcoidosis with a favorable prognosis, others associate it with recurrence and secondary malignancies. Here we describe a series of 7 patients with diagnosis of sarcoma and sarcoidosis seen at a single sarcoma center in South Florida. Methods: Seven patients with diagnosis of both sarcoma and sarcoidosis were identified over the period of 2007 to 2016. Data of presentation, treatment, histology and outcome was tabulated for analysis. The Standardized Incidence Ratio (SIR) was calculated for the state of Florida and for our hospital catchment area. Results: Of the seven patients, 4 cases were GIST, 1 case of unclassified spindled and epithelioid cell sarcoma that coexisted with tenosynovial giant cell tumor, 1 case of uterine leiomyosarcoma, and 1 case of myxofibrosarcoma. Sarcoidosis was diagnosed before sarcoma in 3 patients, after the diagnosis of sarcoma in 3 patients and at the same time of sarcoma diagnosis in 1 patient. All cases of sarcoidosis involved the lungs. From our series, 3 patients have shown no progression of sarcoma, 1 is alive with sarcoma, 2 died due to progression of sarcoma and 1 was lost to follow up. Statistical analyses showed a SIR = 268 (95% CI 106-503), when comparing to the expected incidence in the state of Florida and SIR = 831 (95% CI 329-1562), when comparing to the expected incidence in our catchment area. Conclusions: This case series points to a statistically robust, non-random, association between Sarcoma and Sarcoidosis that has not been previously described. Our study found the lung is not only the most common site of sarcoma metastasis but also the most common site of sarcoidosis. These results infer that patients with presumed metastatic sarcoma should be considered for a biopsy to rule out a benign process such as sarcoidosis. Additionally, the presence of sarcoidosis could be associated with risk of sarcoma. The mechanism of sarcoidosis-associated sarcoma is ongoing.