Management of brain metastasis from eccrine porocarcinoma: illustrative case

BACKGROUND Eccrine porocarcinoma (EP) is a rare malignant skin neoplasm, and there are still many unknowns regarding its natural history and treatment. Due to its scarcity, associated brain metastasis is a far rarer condition. OBSERVATIONS A 71-year-old-woman with a history of EP was diagnosed with brain metastasis. In her clinical course, the patient underwent tumor removal surgery twice and Gamma Knife radiosurgery (GKRS) four times. The tumor showed a good response to radiotherapy. The histopathological findings of the brain tumor were consistent with those of the primary skin tumor. LESSONS There are only a few case reports referring to the detailed treatment, especially with GKRS, of brain metastasis from EP. Few reports have presented a detailed histopathological comparison between the primary skin lesion and the metastatic brain lesion. Herein, the authors have described the clinical course, histological features, and results of multidisciplinary treatment for brain metastasis of EP.

Whole-exome sequencing in eccrine porocarcinoma indicates promising therapeutic strategies

Malignant sweat gland tumours are rare, with the most common form being Eccrine porocarcinoma (EP). To investigate the mutational landscape of EP, we performed whole-exome sequencing (WES) on 14 formalin-fixed paraffin-embedded samples of matched primary EP and healthy surrounding tissue. Mutational profiling revealed a high overall median mutation rate. This was attributed to signatures of mutational processes related to ultraviolet (UV) exposure, APOBEC enzyme dysregulation, and defective homologous double-strand break repair. All of these processes cause genomic instability and are implicated in carcinogenesis. Recurrent driving somatic alterations were detected in the EP candidate drivers TP53, FAT2, CACNA1S, and KMT2D. The analyses also identified copy number alterations and recurrent gains and losses in several chromosomal regions including that containing BRCA2, as well as deleterious alterations in multiple HRR components. In accordance with this reduced or even a complete loss of BRCA2 protein expression was detected in 50% of the investigated EP tumours. Our results implicate crucial oncogenic driver pathways and suggest that defective homologous double-strand break repair and the p53 pathway are involved in EP aetiology. Targeting of the p53 axis and PARP inhibition, and/or immunotherapy may represent promising treatment strategies.

Eccrine Porocarcinoma: A Challenging Diagnostic and Therapeutic Tumoral Entity

Eccrine porocarcinoma is a rare malignant cutaneous tumor with high rates of extracutaneous spread, and its diagnosis and management can be quite challenging. This is a case of an 82-year-old woman presenting with an asymptomatic and chronic pubic skin lesion for whom the work-up required many investigations and procedures to confirm the diagnosis of metastatic eccrine porocarcinoma. Indeed, the patient underwent a wide local excision of the skin lesion, imaging with an FDG-PET scan, a colonoscopy, and two inguinal node dissections. As illustrated in this case, surgery should always be considered to achieve disease remission. Other treatments such as chemotherapy and radiotherapy have also been reported in the literature without clear standard guidelines.