Ectopic extramammary Paget's disease on the head: case report and literature review

Primary Alopecia Neoplastica: A Novel Case Report and Literature Review

Alopecia neoplastica (AN) is caused by neoplastic cells damaging hair follicles, resulting in patchy hair loss like cicatricial alopecia and alopecia areata. AN has predominantly described cutaneous metastasis to the scalp from primary visceral malignant tumors. Less frequently, AN results from a primary scalp neoplasm. Compared to "secondary AN," there is a paucity of literature on "primary AN." Herein, we present a comprehensive literature review of primary AN and introduce a unique case of amelanotic melanoma causing primary AN. Including our presented case, 11 cases of primary AN have been reported with causative scalp neoplasms including angiosarcoma, hemangioendothelioma, syringomatous carcinoma, ectopic extramammary Paget's disease, and primary desmoplastic melanoma. 27.3% (3 of 11) of cases were misdiagnosed and treated for a primary alopecia, and 36.4% (4 of 11) of lesions were present for multiple years or an unknown amount of time, likely due to difficulty in recognizing scalp lesion or misdiagnosis. All patients required surgical excision with 36.4% (4 of 11) requiring chemotherapy, radiation, or photodynamic therapy. Two patients with scalp angiosarcoma died from their aggressive disease. Due to the risks of malignant primary AN if allowed to progress, primary AN should be considered in patients presenting with scarring alopecia.

RANKL-Expressing Ectopic Extramammary Paget's Disease on the Lower Abdomen

Ectopic extramammary Paget's disease (EMPD) is a rare variant of EMPD that develops in nonapocrine regions. Since reports about ectopic EMPD are limited, little is known about the biological and immunological background of ectopic EMPD. In this report, we present a case of ectopic EMPD on the lower abdomen that expressed RANKL but lacked the expression of MMP7. As we previously reported, Paget's cells express RANKL and MMP7, release soluble RANKL in the tumor microenvironment, and stimulate tumor-associated macrophages to produce tumor-loading factors in conventional EMPD. In our present case, both CCL5-expressing cells and MMP25-bearing cells were lacking, whereas substantial numbers of CCL5-expressing cells and MMP25-bearing cells were found in conventional EMPD. Our case suggested that the lack of MMP7 on Paget's cells might be one of the possible explanations for the biology of ectopic EMPD.