A-57-year-old female patient presented at our institution with an apparently slow growing and painful perianal mass, which had produced some serous discharge for the preceding several years. The woman denied any history of constipation or anal bleeding, and she also denied any history of major disease including malignancy. Digital examination revealed a huge (5 × 5 × 5 cm), well-defined solid tumor associated with a skin ulcer, which was located over the left posterior region of the buttock adjacent to the anus. Tracing back her surgical history, this patient had undergone perianal skin tumor excision twice previously, once in 1981 and again in 1992. On both occasions, this was due to the presence of a painful perianal mass. According to her description of the previous perianal masses, they were firm and slow growing, and featured associated skin ulceration. The pathology report for the mass removed in 1992 at our hospital stated it was a 5 × 5 × 3 cm perianal syringocystadenoma papilliferum. During the surgical procedure conducted in 1992, the surgical wound was repaired with a rotation skin flap as there was a rather large skin defect. She was free of disease between the two surgeries for about 8 years. Laboratory data, including complete blood count and relevant blood biochemistry, were unremarkable. Under the initial impression of a perianal fistula or perianal skin tumor, incision biopsy was performed. The biopsy specimen was sent for frozen section examination, which revealed malignant neoplasm with myoepithelial-like proliferation. Following this histopathology report, en-bloc excision was undertaken in order to excise the tumor with a gross margin of 2 cm. The post-surgery wound was left to heal openly without resorting to flap closure. Subsequent to surgery, metastatic work-ups revealed multiple nodules over both of the patient's lungs, presumably secondary to the primary malignant neoplasm. Other examinations, including immunological tumor markers (CA 19-9: 16.5; CEA: 0.2; CA 125: 15.4; SCC: 0.2), sputum cytology and gynecological ultrasonography, were performed and all produced unremarkable results. The final pathology report suggested the presence of an eccrine adenocarcinoma. Microscopically, lesion sections revealed hyperchromatic neoplastic cells arranged in solid nests, anastomosing trabeculae with ductular formation, a syringoid tubular or cord-like pattern, and irregular cribriform glandular structures (revealing an adenoid cystic carcinoma-like pattern) with irregular infiltrative tumor margins. The tumor cells were characterized by the presence of mild to moderate nuclear pleomorphisms, occasional distinct nucleoli, not uncommon mitotic activity, and a variable amount of eosinophilic, basophilic or clear cytoplasm featuring focal tumor necrosis. Perineural invasion and lymphovascular space permeation were also noted. Immunohistochemically, the proliferated stromal cells and peripheral cells of the tumor nest or glandular structures were focally positive for SMA. The luminal tumor cells and central cells of the tumor nests were variably positive for polyclonal CEA and CK7. All of the neoplastic cells were negative for EMA, CDX2 and TTF-1, and no evident tumor cell mucin production was seen on mucicarmine and DPAS staining. The cancer invaded the dermis and subcutis. The epidermis was spared and free of pagetoid involvement.