Metastatic SMARCB1 Deficient Skin Carcinoma With Neuroendocrine Differentiation in the Parotid Glands Clinically Mimicking Primary Salivary Gland Malignancy: Unusual Case With Diagnostic Pitfalls.

BACKGROUND/AIM: SMARCB1(INI1)-deficient cutaneous carcinomas are an emerging subset of rare tumors, with only a few cases reported, making its diagnosis challenging. CASE REPORT: A 84-year-old male with a history of prostate adenocarcinoma and skin squamous cell cancer presented with a rapidly growing upper neck mass. Computed tomography (CT) and positron emission tomography (PET)/CT scans were suspicious of a salivary gland neoplasm of the parotid glands. Needle core biopsy of the right parotid gland mass showed poorly differentiated carcinoma. The patient underwent bilateral superficial parotidectomies and neck lymph nodes dissection. Histologically, the tumor showed rhabdoid and plasmacytoid morphology with diffuse loss of SMARCB1, positive deltaNp63 (p40), focally positive synaptophysin, and 80% of Ki67 index. Retrospectively, SMARCB1 deficiency carcinoma with squamous and neuroendocrine differentiation was confirmed in the prior skin lesion of the right frontal scalp. The patient had a poor prognosis even though post-surgical radiation therapy was given. CONCLUSION: We present a unique case of metastatic SMARCB1-deficient cutaneous carcinoma in the parotid glands with both squamous and neuroendocrine differentiation. This entity should be considered in any difficult-to-classify skin carcinoma, as timely definitive diagnosis will be mandatory for optimizing therapy.

HIV-related Neuropathy: Pathophysiology, Treatment and Challenges.

HIV-sensory neuropathy (HIV-SN) is a debilitating complication in HIV patients with or without anti-retroviral treatment (ART). Common symptoms of HIV-SN include pain, decreased sensation, paresthesias, and dysesthesias in a symmetric stocking-glove distribution. While HIV-1 protein such as gp120 is implicated in HIV-SN (e.g. impaired large-diameter fiber), ART itself was recently shown to contribute to HIV-SN in HIV patients and impair thin fiber. Multiple host mechanisms may play roles during the pathogenesis of HIV-SN, including neuron-glia interactions in the spinal dorsal horn (SDH), inflammation, mitochondrial dysfunction and endoplasmic reticulum stress. Concurrent infections, such as tuberculosis, also carry a higher likelihood of HIV-SN as well as environmental or genetic predisposition. Pro-inflammatory cytokines such as IL-1, IL2 receptor-alpha, and tumor necrosis factor (TNF) along with abnormal lactate levels have been identified as potential players within the complex pathophysiology of this condition. In this paper, we review the pathophysiology of HIV neuropathy, focusing on the various treatment options available or under investigation. Although several treatment options are available e.g., the capsaicin patch and spinal cord stimulation, symptomatic control of HIV-SN are often challenging. Alternative approaches such as self-hypnosis, resistance exercise, cannabinoids, and acupuncture have all shown promising results, but need further investigation.