The Pathological Culprit of Neuropathic Skin Pain in Long COVID-19 Patients: A Case Series

Cutaneous neurosensory symptoms have become increasingly reported findings in COVID-19; however, these virus-related manifestations are largely overlooked, and their pathology is poorly understood. Moreover, alterations of skin sensibility currently recognize no clear histopathology substrate. The purpose of this study was to provide pathology evidence of neurosensory skin system involvement in COVID-19 patients complaining of subjective neurological symptoms affecting the skin. Out of 142 patients, six long COVID-19 cases complaining of cutaneous subjective neurological symptoms assessed on an NTSS-6 questionnaire underwent histopathological and immunohistochemical analyses of skin areas affected by paroxysmal diffuse burning and itching sensations. Two patients also performed electroneurography examination. The histology investigation showed hypertrophic glomus vascular bodies with hypertrophic S100+ perineural sheath cells and adjacent hypertrophy of the nerve branches associated with increased basophil polysaccharide matrix. Electroneurography revealed disturbances of A-delta and C dermal neuronal fibers. The main limitation of this study consisted of a limited number of skin biopsy samples, requiring further investigation. Histopathology findings are consistent with hypertrophy of nerve endings, suggesting a condition such as “dermal hyperneury”, a recently reported small nerve hypertrophy condition affecting sensory C fibers. Such a neuropathic basis could explain dysesthesia experienced by the patients, as previously described in postherpetic neuralgia.

Overview of the 2022 WHO Classification of Familial Endocrine Tumor Syndromes

This review of the familial tumor syndromes involving the endocrine organs is focused on discussing the main updates on the upcoming fifth edition of the WHO Classification of Endocrine and Neuroendocrine Tumors. This review emphasizes updates on histopathological and molecular genetics aspects of the most important syndromes involving the endocrine organs. We describe the newly defined Familial Cancer Syndromes as MAFA-related, MEN4, and MEN5 as well as the newly reported pathological findings in DICER1 syndrome. We also describe the updates done at the new WHO on the syndromic and non-syndromic familial thyroid diseases. We emphasize the problem of diagnostic criteria, mention the new genes that are possibly involved in this group, and at the same time, touching upon the role of some immunohistochemical studies that could support the diagnosis of some of these conditions. As pathologists play an important role in identifying tumors within a familial cancer syndrome, we highlight the most important clues for raising the suspicious of a syndrome. Finally, we highlight the challenges in defining these entities as well as determining their clinical outcome in comparison with sporadic tumors. Instead of the usual subject review, we present the highlights of the updates on familial cancer syndromes by answering select questions relevant to practicing pathologists.

Dermal hyperneury

Dermal hyperneury (DN) is a rarely reported form of small nerve hypertrophy characterized by an exaggerated size and prominence of dermal nerve fibers. Clinically, it can present with or without visible lesions, within a syndrome or sporadically, and in solitary or multiple fashion. The syndromes most commonly associated with DN include multiple endocrine neoplasia 2B and 2A, neurofibromatosis type II, and Cowden syndrome. Patients with syndrome-associated DN have an increased risk for various malignancies. Sporadic DN has been reported either in association with cutaneous tumors/reactive lesions, such as nodular prurigo, or in idiopathic form, where it can present with multiple DN lesions. There is a morphologic overlap between mucocutaneous neuromas and DN, as the former can have the appearance of either bulkier circumscribed lesions or tortuous and hyperplastic nerves more akin to DN. Epithelial sheath neuroma also shares a similar appearance to DN, from which it can be distinguished by a squamoid-appearing and thickened perineurium.