Paget's disease of the vulva complicated by bladder carcinoma. Case report

Characteristic Clinicopathological Features of Secondary Extramammary Paget Disease With Underlying Anorectal Adenocarcinoma: Evenly Circumferential Perianal Distribution, Fibroepithelioma of Pinkus-like Changes, and Subepidermal Mucin Deposits Without Invasive Tumor Cells

ABSTRACT

This study aimed to identify the clinical and histopathological characteristics of secondary extramammary Paget disease (EMPD) with underlying anorectal adenocarcinoma so as to differentiate it from primary cutaneous EMPD. Seventeen and 8 cases of primary and secondary EMPD with anorectal adenocarcinoma, respectively, were retrieved from the pathology archive and the clinical and histopathological features reviewed. The tumor samples from 21 cases were totally resected specimens, whereas 3 and 1 of secondary and primary cases were punch biopsied, respectively. All 8 (100%) cases of secondary EMPD presented evenly distributed perianal lesions. By contrast, 4 of 17 (23.5%) primary EMPD cases had perianal skin lesions and displayed an uneven, asymmetrical distribution around the anus. Fibroepithelioma of Pinkus-like changes and subepidermal mucin deposits with no or few invasive tumor cells were observed in 6 (75%) and 3 (37.5%) of the 8 secondary EMPD cases, respectively, although 3 secondary case samples were small biopsy specimens. Both the histopathological changes were not observed in any of the 17 primary EMPD cases. Evenly circumferential perianal distribution, fibroepithelioma of Pinkus-like changes, and subepidermal mucin deposits without invasive tumor cells were characteristic to cases of secondary EMPD with anorectal adenocarcinoma. These clinicopathological features could be used to differentiate between secondary and primary EMPD.

Epidermotropically metastatic breast carcinomas. Rare histopathologic variants mimicking melanoma and Paget's disease

Epidermotropic metastases from internal malignancies are exceedingly rare. We report two examples of epidermotropic metastatic breast carcinoma with striking intraepidermal involvement. The first case mimicked melanoma because the neoplastic cells contained melanin and were disposed both as single units and as nests at the dermoepidermal junction and throughout the epidermis. In the second case, the neoplastic cells were seen as isolated neoplastic cells with large, pale cytoplasm scattered throughout the epidermis, closely resembling extramammary Paget's disease. Immunohistochemical studies in both cases demonstrated the epithelial nature of intraepidermal neoplastic cells, which showed an immunophenotype identical to the neoplastic cells present in the dermis: positive staining with anti-cytokeratins, CEA, EMA, and GCDFP-15 and negative with anti-S-100 protein and HMB-45. These findings ruled out the possibility of a collision lesion, or simultaneous occurrence of melanoma and metastatic breast carcinoma. Pagetoid intraepidermal spread of metastatic breast carcinoma, as in our two cases, is exceptional. We also discuss the histogenetic similarities between our findings and those of mammary and extramammary Paget's disease, as well as the differential diagnosis of other cutaneous disorders characterized by pagetoid intraepidermal spread of neoplastic cells.

Extramammary Paget's disease: an annotated review

The incidence, clinical features, histogenesis, and treatment of extramammary Paget's disease (EMPD) are reviewed. This unusual skin lesion is associated with an underlying adnexal neoplasm in about 50% of cases. Also, the incidence of distant organ malignancies of EMPD is higher than expected by chance. Even in the absence of a recognizable underlying cancer, EMPD may occasionally produce distant metastases, indicating the malignant potential of this condition. Histochemical, immunohistological, and lectin binding studies demonstrate that the cell of origin of EMPD is the exocrine cell of sweat glands. Although EMPD may arise from eccrine cells, derivation from apocrine cells appears more common. The treatment of the primary lesion, by wide margin excision, is fraught by a high recurrence rate. Chemosurgery may reduce local relapse of EMPD. The value of adjuvant radiation therapy is unestablished. Chemotherapy has induced remission in 2 cases of advanced EMPD and needs testing in clinical trials.