Co-occurrence of Dermatomyositis and Polycythemia Unveiling Rare de Novo Neuroendocrine Prostate Tumor

Abstract

We present a case of dermatomyositis together with polycythemia as initial manifestations of a particularly rare type of prostate cancer. A 69-year-old man was hospitalized for facial erythema and symptoms of fatigue. Physical evaluation, serum creatinine phosphokinase and electromyography were consistent with dermatomyositis. In parallel, the hemoglobin level was 18.5 g/dL, serum erythropoietin levels were low normal and no JAK2 mutation was found. Given a strong suspicion of a paraneoplastic syndrome the patient underwent abdominal computed tomography revealing a prostate mass, enlarged iliac lymph nodes and a fracture of L1 due to metastasis. The unusual paraneoplastic manifestations prompted a more thorough immunohistologic examination of the needle biopsy specimen taken from the prostate, which led to the diagnosis of large cell neuroendocrine prostate carcinoma. It is a most rare type of prostate cancer, carrying a poor prognosis. To our knowledge, this is the first case in the literature associating a neuroendocrine cancer of the prostate with dermatomyositis.

Morphologic Spectrum of Neuroendocrine Tumors of the Prostate: An Updated Review

“…Tumor cells of LCNC express one or more NE markers (SYN, CgA, or CD56), with variable expression of PSA, PAP, CK7, and CK20. 56,57 The LCNCs are usually negative for AR. Ki-67 labeling index often exceeds 50%.…”

“…51 Paraneoplastic syndrome of co-occurrence of dermatomyositis and polycythemia has also been reported. 56…”

A Rare Association Between Prostate Cancer and Polycythemia Vera

“…Papagoras et al published a case report on the association of dermatomyositis and neuroendocrine prostate cancer in a patient with PV [ 16 ]. Physical evaluation, electromyography, and serum creatinine phosphokinase in keeping with dermatomyositis.…”

Incidental finding of a small cell neuroendocrine carcinoma of the ureter

“…This may be due to the high incidence of adenocarcinoma of the prostate, where prostatic NET can exist concomitantly following long-standing hormonal therapy, or in the context of therapeutic resistance in metastatic castration resistant prostate cancer 19–23. It has also been reported in association with dermatositis and polycythaemia 24. NETs of the ureter and prostate share the same microscopic morphology and immunohistochemical staining patterns, along with all NETs of the urinary tract.…”