A 39-year-old Japanese male presented with a 3 months history of a skin tumor on the left side of the jaw. Past medical history revealed lung tuberculosis at age 20 years old. Physical examination showed a dome-shaped, slightly erythematous nodule measuring approximately 2 cm in diameter (Fig. ). Preoperative examination revealed no lymph node or distant metastasis. Punch biopsy was performed, and it was diagnosed as mucinous adenocarcinoma of the skin.\nThe tumor was excised with 5-mm surgical margin and was reconstructed with local rotational flap. The definitive histopathology showed small cellular nests of adenocarcinoma lying in pools of extracellular mucin that were separated by fibrocollagenous septae without involvement of underlying muscle. (Figure a,b) The immunohistochemical staining revealed that the tumor cells were positive for CK7, epithelioid membrane antigen (EMA), MUC1, MUC2, estrogen receptor (ER), and progesterone receptor (PR).\nThe patient again noticed a small tumor on the left side of the jaw in the area of the previous operation site 2 years after the primary operation. However, the patient had chosen not to be examined by a physician and left it alone for 4 years. Because of the rapid growth of the tumor, the patient visited our clinic. At this point, the tumor measured approximately 6 cm in diameter (Fig. a). Preoperative examination revealed invasion of the mandible and one left neck lymph node metastasis. The lesion was excised with at least 1-cm border of normal skin including the mandible (Fig. ). A left radical neck dissection was performed, and the mandible was reconstructed with a free scapula flap. The definitive pathology revealed MCS recurrence with no residual tumor cells in the excised normal skin area. One of 20 regional lymph nodes contained metastasis. Postoperatively, the patient was free of tumor and was followed up by the physician in charge every 3 months for 5 years and every 6 months for the next 5 years. The patient was disease-free for ten consecutive years on physical examination, chest X-ray, neck echogram, and ordinary blood test. Although the patient did not have any symptoms, the chest X-ray at the 11th year follow-up revealed multiple lung metastases (Fig. a,b). Additional chest computed tomography (CT), magnetic resonance imaging (MRI), and RI showed cervical vertebrate (Th5) tumor, and biopsy revealed metastasis of MCS. The patient received radiotherapy for pain control and died 3 year after the diagnosis of metastasis.
A 71-year-old man visited our hospital with a raised nodular mass of size 2×3×1 cm in his left groin and an erythematous area of 9×10 cm over the left groin (). He had first noticed the erythema and nodules 6 months before he visited our hospital. The erythema had gradually expanded in size. Ulceration with intermittent bleeding was noted within the nodular mass. On physical examination, edema of the left leg was observed, and lymph nodes in both inguinal regions were palpable. The results of routine hematological and biochemical examinations were normal. Examination of skin biopsies from the inguinal folds revealed features of EMPD in the epidermis and underlying glandular neoplastic foci in the reticular dermis and in the subcutaneous adipose tissue (). Moreover, focal angiovascular invasion was noted. Typical Paget cells were scattered in the epidermis (). The glandular neoplastic foci resembled carcinoma in situ. Some foci showed accumulation of secretion in central regions (). The tumor cells exhibited abundant eosinophilic cytoplasm and large vesicular nuclei.\nThe tumor and Paget cells showed strong positive immunohistochemical staining for carcinoembryonic antigen (CEA), epithelial membrane antigen, cytokeratin 7 (CK7), and gross cystic disease fluid protein-15 (GCDFP-15) () but were negative for melanin-A, S-100, and CK20 (). The patient was diagnosed with apocrine carcinoma related with extensive EMPD. Chest radiography, abdomino-pelvic computed tomography (CT), a gallium scan, a bone scan, and positron emission tomography-CT were performed to exclude the presence of internal malignancy. The results showed multiple lung, bone, and lymph node metastases. After consultation with a urologist and a surgeon, we concluded that this patient was inoperable, and opted for conservative treatment; however, the patient refused any treatment.