Syringocystadenocarcinoma papilliferum (SCACP) is a rare malignant adnexal neoplasm, which is considered as a malignant counterpart of syringocystadenoma papilliferum (SCAP). Clinically, SCACP appears as a nodule, inflammatory plaque, or tumor. The lesion is usually covered with crusts, which are formed by secretion of the apocrine epithelial cells. Histologically, SCACP resembles SCAP, with cystic papillomatous invaginations connected to the skin surface by funnel-shaped structures lined by infundibular epithelium. The stroma of the tumor consists of a dense inflammatory infiltrate of plasma cells and lymphocytes. SCACP differs from SCAP in terms of the architectural and cytological features of the tumor cells, and is characterized by higher nuclear cytoplasmic ratio, nuclear irregularity, coarse chromatin, and increased mitotic activity. However, the immunohistochemical findings of SCACP vary. Since only 49 cases of SCACP have been reported in the English literature, the clinical and histologic characteristics of SCACP have not been fully established. Further studies on the diagnostic criteria for SCACP are warranted. Here, we report a rare case of SCACP and present a review of other relevant literature.

Poroid hidradenoma (PH) is a rare benign tumor that shows differentiation of the eccrine sweat gland. It occurs mainly in adults, presenting as a 0.5 to 2 cm-sized intradermal nodule, mostly on the head, extremities, trunk and neck. We report two rare cases of PH, one on the face and the other on the heel. The first patient was a 50-year-old male who had a solitary, skin-colored nodule on his right temple for 6 months. The second patient was a 67-year-old female who presented with a solitary, bean-sized, tender nodule on her left heel for 1 year. The common histological examination finding was a well-circumscribed tumor composed of solid portions and large cystic spaces in the center. The tumor cells consisted of small, monomorphic poroid cells and large cuticular cells in both cases. To our knowledge, only few cases of PH have been reported. Herein, we report two rare cases of PHs with literature review.