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

In patients with sarcoma, concomitant malignancy is found in 1.2% -2.5% of cases. Previous studies have demonstrated conflicting results in terms of positive or negative effects on cancer prognosis with comorbid sarcoidosis. Additionally, there are no data determining whether an association between sarcoidosis and sarcomas exists. Finding an association between the two entities could prevent inadvertent upstaging of a primary sarcoma based on pulmonary nodularity mistaken for metastatic disease. Here, we will describe eight sarcoma patients with concomitant occurrence of sarcoidosis identified since 2007. Eight patients with diagnosis of both sarcoma and sarcoidosis were identified over the period of 2007 -2016 at a single sarcoma center. Clinical and historical data including presentation, histology, treatment, and outcome was tabulated for analysis. The standardized incidence ratio was calculated for the state of Florida and our hospital catchment area. We compared the observed incidence to the expected incidence if the two entities were to be unrelated. Sarcoma subtype was gastrointestinal stromal tumor in five patients, the remaining three cases were unclassified spindled and epithelioid cell sarcoma, uterine leiomyosarcoma, and myxofibrosarcoma. Sarcoidosis was diagnosed before sarcoma in three patients, after sarcoma in four patients, and at the same time of sarcoma diagnosis in one patient. From our series, three patients have shown no progression of sarcoma, two are alive with sarcoma, two died due to progression of sarcoma, and one was lost to follow up. Statistical analyses showed a standardized incidence ratio of 305 (95% confidence interval: 131 -556) for the state of Florida and standardized incidence ratio of 950 (95% CI: 407 -1727) for our catchment area. This case series points to a statistically robust, nonrandom association between sarcoma and sarcoidosis that has not been previously described. Presumed metastatic sarcoma should be considered for biopsy particularly with demographic characteristics or imaging features suggestive of sarcoidosis.