Left gluteal focal myositis in a patient with signet ring adenocarcinoma of the stomach: not a paraneoplastic phenomenon.

Focal myositis, the much rarer clinical and pathological variant of polymyositis, is generally a benign inflammatory pseudotumor of skeletal muscle Thus far, only three cases have been reported in association with a neoplasm. We now describe a fourth case of localized gluteal myositis seen in a case of signet ring adenocarcinoma of the stomach occurring not as a paraneoplastic syndrome, as in the previously reported three cases, but as an immunoinflammatory response around metastatic cell foci in both the involved muscles and local lymphatics.