Dermatomyositis accompanied by prostatic cancer and elevated serum CA 19.9

Identification of autoantibodies elicited in a patient with prostate cancer presenting as dermatomyositis

OBJECTIVES

Dermatomyositis is an uncommon autoimmune disease distinguished by proximal muscle weakness and a characteristic skin rash. Dermatomyositis has also frequently been associated with malignancy, typically heralding the diagnosis of ovarian, lung, gastric, or colorectal cancer. We report an unusual case of prostate adenocarcinoma preceded by a diagnosis of dermatomyositis. We hypothesized that in this particular patient, proteins produced by the neoplastic prostatic tissue, which might be normally expressed in muscle tissue, were immunologically recognized as autoantigens.

METHODS

Serum from this patient was used to screen a cDNA lambda phage expression library from normal prostate tissue for prostate protein-specific IgG.

RESULTS

We identified several immunoreactive plaques encoding known autoantigens, and several encoding known muscle-related proteins, including aldolase C, eukaryotic translation elongation factor 1 alpha 1, transgelin, and acetyl-coenzyme A acyltransferase 1. IgG specific for these proteins were not specifically recognized in sera from other patients with prostate cancer compared with male control blood donors, and were not specifically recognized in a small panel of sera from patients with breast or ovarian cancer and dermatomyositis.

CONCLUSIONS

Our results demonstrate that this patient with prostate cancer presenting as dermatomyositis had autoantibodies to specific proteins, possibly associated with his autoimmune myopathy. Moreover, given this patient's history and the multiple treatment options for prostate cancer, the identification of dermatomyositis in men should prompt an evaluation to exclude a concurrent diagnosis of prostate cancer.

Neurologic complications of solid tumors

This article reviews the neurologic complications of the most common solid tumors, including lung, breast, gastrointestinal, genitourinary, gynecologic, head and neck cancers, melanoma and sarcomas. As systemic therapy improves for many of these tumors, patients are surviving longer and the incidence of neurologic complications is increasing.