REPORT OF A CASE
A 71-year-old man was referred for evaluation of an asymptomatic skin eruption that had been present on the lower aspect of his abdomen for approximately 10 weeks.The physical examination revealed innumerable 2- to 3-mm, firm, freely moveable, violaceous deep papules and about 12 3- to 10-mm exophytic, firm, orange-to-red hairless papulonodules (Fig 1). The lesions were limited to the lower abdominal, suprapubic, and inguinal skin.Routine hematologic and biochemical tests showed normal findings except for mild anemia (hemoglobin, 110 g/L; hematocrit, 0.34). Serum acid phosphatase and carcinoembryonic antigen levels were mildly elevated.A punch biopsy specimen was obtained from a typical lesion. Histologic findings are depicted in hematoxylin-eosin-stained sections (Figs 2 and 3). Immunohistochemical staining for acid phosphatase is shown in Fig 4.What is your diagnosis?
DIAGNOSIS:
Metastatic carcinoma of the prostate.
HISTOPATHOLOGIC FINDINGS
The biopsy specimen revealed infiltration of the dermis by islands of cells arranged in a glandular fashion consistent with