YAP1::MAML2 fusions in poromatosis: A report of two patients.

Poromatosis is a rare condition characterized by the development of multiple poromas, mainly reported in patients with a history of malignancy. Recently, frequent YAP1::MAML2 and YAP1::NUTM1 fusions have been described in poromas and porocarcinomas. To date, the molecular features of poromatosis have been investigated in one patient only, wherein the poromas harbored YAP1::MAML2 fusions. Herein, we present two additional cases of poromatosis with YAP1::MAML2 fusions. Case 1: An 81-year-old woman presented with nine papules on the scalp, trunk, and extremities persisting for a year. She had a history of breast cancer, with no information on the treatment. Seven papules were excised. Case 2: A 65-year-old woman presented with 21 lesions on her trunk and lower extremities persisting for 2 years. She had been diagnosed with breast cancer 11 years prior and had undergone partial mastectomy, radiotherapy, chemotherapy, and endocrine therapy. Four lesions were excised. All 11 lesions in both patients were histopathologically similar: anastomosing cords and strands extending from the epidermis, and poroid and cuticular cell proliferation with interspersed small ducts. The tumors showed diffuse nuclear expression of YAP1 N-terminus and loss of YAP1 C-terminus expression. No lesions showed NUT immunopositivity. Sanger sequencing identified YAP1::MAML2 fusions in the poromas of both patients.

Multiple Plantar Poromas in a Stem Cell Transplant Patient.

Poromatosis, or the formation of multiple eccrine poromas, is associated with chronic immunosuppression, lymphoproliferative neoplasms, and stem cell transplantation, though the etiology and clinical significance remain poorly understood. Eccrine poromas are asymptomatic, may appear years after treatment, and overlap morphologically with other diagnoses, particularly human papillomavirus-associated verrucae, to which immunosuppressed patients may be predisposed and commonly occur in similar sites. We report a 47-year-old female on chronic immunosuppression who developed multiple plantar eccrine poromas three years after achieving acute myeloid leukemia (AML) remission following treatment with chemotherapy, total body irradiation, and allogenic stem cell transplantation. We propose that early recognition, timely treatment, and regular follow-up skin examinations are necessary in the setting of multiple poromas to reduce the risk of malignancy and avoid delays in diagnosis.

A Case of Eccrine Poromatosis in a Patient with a History of Chemotherapy Due to Stomach Cancer.

An eccrine poroma (EP) is a benign adnexal tumor that typically presents as a single lesion. Eccrine poromatosis defined as multiple EPs is an uncommon presentation. A 54-year-old male had undergone operation for stomach cancer 10 years prior and insisted that he had also taken adjuvant chemotherapy. The patient presented with six reddish papules and nodules scattered on the trunk and extremities for 3 years. The histopathologic findings from all six lesions were consistent with EP. No local recurrence was observed after complete removal through punch biopsies. We report a rare case of eccrine poromatosis in the patient with gastric cancer, suspected of being caused by chemotherapy.

Eruptive poromatosis in a patient with breast cancer.

Poromas are a group of benign growths of poroid differentiation derived from cells of the terminal sweat duct and connected to the epidermis, normally presenting as solitary papules, plaques or nodules. Rarely they can be eruptive in nature and as such are described as poromatosis. We report an unusual case of widespread poromatosis occurring in a woman with metastatic breast cancer who had recently completed chemo-radiotherapy.

Eccrine Poromatosis: Case Report, Review of the Literature, and Treatment.

Eccrine poromas arise from the intraepidermal region of the eccrine sweat duct and most often occur as a benign solitary tumor. There are few reports of the occurrence of multiple lesions, defined as poromatosis, which may present in patients who have undergone radiotherapy and/or polychemotherapy. We report the case of a 43-year-old male with a history of mantle cell lymphoma who had undergone 6 cycles of polychemotherapy. He presented to the dermatology clinic for multiple painful lesions on his palms and soles. Several biopsies were performed consistent with eccrine poromas. The patient was successfully treated with a combination of excision, imiquimod cream, and cryosurgery. This case adds to the literature regarding the pathogenesis and treatment options of eccrine poromatosis. Herein, we report a case of eccrine poromatosis that developed after 6 cycles of chemotherapy.