Spectrum of Clinicopathologic Findings in COVID-19-induced Skin Lesions: Demonstration of Direct Viral Infection of the Endothelial Cells.

The novel coronavirus disease (COVID-19) is a rapidly spreading pandemic, secondary to severe acute respiratory syndrome coronavirus 2. The severity and the little knowledge that we have of the disease have made us focus mostly on the respiratory symptoms. As we bend the curve, other findings reported in association with COVID-19 become of importance for specialists to recognize. We describe the spectrum of clinicopathologic lesions in the skin that can be the only symptom or the first manifestation of COVID-19 and demonstrate the origin of the virus. We collected 25 patients with skin lesions in this context. We recognized 5 types of cutaneous manifestations including acute acroischemic or chilblain-like lesions (11), purpura palpable (2), exanthemas (9), urticarial eruptions (1), and other lesions (2) that might appear with more unspecific pictures. Chilblain-like lesions were the most common form of presentation, which tend to appear as self-healing, erythematous-necrotic plaques mostly on the feet, in young patients with no systemic symptoms associated. Importantly, we visualized viral particles with electron microscopy in 5 of 13 cases analyzed. In this study, we seek to draw a picture of the spectrum of clinicopathologic lesions that may appear in the skin in the context of COVID-19. Although apparently skin lesions are not correlated with disease severity, it may help in some cases to recognize and control the spread of the infection sooner.

Three Cases of Clear Cell Hidradenoma With "Benign" Lymph Node Involvement.

ABSTRACT: The malignant counterpart of cutaneous clear cell hidradenoma (CCH), hidradenocarcinoma, is an aggressive neoplasm that may have a fatal outcome. However, some cases of benign looking CCH with isolated lymph node involvement and excellent prognosis have been described. "CCH-like neoplasm of uncertain malignant potential" or "atypical hidradenoma" have been proposed as designations for these lesions. We report 3 cases of CCH with lymph node involvement. Ages ranged from 29 to 51 years old. All cases involved the inguinal lymph nodes: 2 of them presented with an isolated lymph node lesion, and the third case had lymph node and cutaneous involvement following the resection of a previous cutaneous lesion. Imaging studies showed no systemic involvement. None of the lesions exhibited histopathologic features of malignancy. All neoplasms were well circumscribed, had cystic spaces, did not display atypia or necrosis, and had less than 4 mitoses per high power field. No recurrence has been observed at follow-up after resection in all cases. All published cases of CCH with lymph node involvement so far affected a single lymph node in the axillary or inguinal regions, lacked features of malignancy, and had excellent long-term prognosis. Some cases previously reported as hidradenocarcinoma probably fit into this category. Our series adds more evidence to this rare phenomenon of "benign metastasis." Aggressive treatment should be avoided in these cases, and a long-term follow-up is warranted.

The immunohistochemical profile of Spitz nevi and conventional (non-Spitzoid) melanomas: a baseline study.

Several isolated markers have been proposed to aid in differential diagnostic of difficult melanocytic lesions, albeit none has been shown to be definitive in differentiating Spitz nevus from melanoma. This study proposes a wide panel of 22 markers having important functions in different biological functions (cell cycle, apoptosis, DNA repair proteins and membranous receptors) to provide a combination of proteins associated with either benign or malignant phenotype. Using tissue microarrays, we compared protein expression profiles in 28 typical Spitz nevi and 62 primary vertical growth phase non-spitzoid melanomas. Most of the significant differences were linked to cell-cycle deregulation such as overexpression of cyclin D1 and p21 in Spitz nevi compared with non-spitzoid melanomas (74 vs 16% and 91 vs 27%, respectively) and mitotic rate including Ki-67, highly expressed in deep areas of non-spitzoid melanomas (37%), whereas it is not expressed in Spitz nevi (0%), topoisomerase IIalpha (79% in non-spitzoid melanomas vs 15% in Spitz nevi) and nuclear survivin (69% in melanomas vs 0% in Spitz nevi). A combination of biological markers differentially expressed in Spitz nevi from non-spitzoid melanomas is defined, thus providing a potential tool for histopathological differential diagnostic between Spitz nevus and melanoma. Nevertheless, more studies including atypical Spitz nevi and spitzoid melanomas are necessary to further establish a reliable panel to differentiate among difficult cases.

Subcutaneous atypical fibrous histiocytoma.

Benign fibrous histiocytoma is one of the most frequent benign neoplasms mainly composed of a mixture of fibroblastic and histiocytic cells, especially found in the skin (dermatofibroma), particularly in the limbs. The diagnosis of cutaneous benign fibrous histiocytoma is generally easy; however, rare variants may be difficult to identify, and the diagnosis only confirmed after exhaustive histopathological examination. Thus, deep subcutaneous dermatofibroma may be difficult to distinguish from dermatofibrosarcoma protuberans and dermatofibroma with monster giant cells from malignant fibrous histiocytoma and atypical fibroxanthoma. We report a case of a 38-year-old woman with a painless swelling on the abdominal wall, which was totally excised and histopathologically diagnosed as subcutaneous atypical fibrous histiocytoma. The lesion was deeply located within the subcutaneous tissue and consisted of interlacing fascicles of predominant histiocyte-like spindle cells intermingled with pleomorphic giant cells with bizarre large nuclei (bilobed and multilobed) and prominent eosinophilic nucleoli. Only 1 mitotic figure was found in the whole lesion. Prominent hyaline collagen bundles surrounded by tumor cells were observed, predominantly at the periphery of the lesion. Immunohistochemical study showed positivity only for vimentin and factor XIIIa, whereas pan-keratins, actin, desmin, CD34, CD10, and S-100 protein were negative. Recognition of dermatofibroma is important, allowing sequential excision and optimal results. Definitive diagnosis, although especially difficult in our case, is established by characteristic histological and immunohistochemical criteria. To the best of our knowledge, we report the first case of subcutaneous fibrous histiocytoma with monster cells.

Eruptive syringoma developed over a waxing skin area.

Syringomas are benign, eccrine, sweat gland tumors that clinically appear as small skin-colored or yellow papules. Eruptive syringomas are rare variants that typically develop on the body's cutaneous anterior surface. Syringomas on the genital area have rarely been reported, although several authors maintain that syringoma should be considered in the differential diagnosis of pubic pruritic papular dermatitis. We present a case of a 31-year-old man with multiple, eruptive, asymptomatic papules involving the pubic area developed after waxing of the zone. Histological examination revealed disseminated syringomata. We postulate that the lesions were induced by depilation with a subsequently reactive inflammatory process resulting in a hyperplastic reaction of the eccrine ducts. This case supports the previous hypothesis suggesting that some of the so-called "eruptive syringomas" may start as a primary inflammatory eccrine reaction.

Lichenoid sarcoidosis: a case with clinical and histopathological lichenoid features.

Sarcoidosis is a chronic multisystemic granulomatous disease of unknown etiology, characterized by the formation of noncaseating granulomas in the involved organs. Cutaneous involvement is about 25% with different clinical expressions, the lichenoid pattern being one of the rarest types of cutaneous sarcoidosis. Lichenoid sarcoidosis clinically manifests with multiple scale papules involving extensive skin areas, especially the trunk, limbs, and face mimicking a lichen planus. Although diverse histologic patterns have been previously related, a lichenoid granulomatous infiltrate involving the dermo-epidermal junction has never been reported in lichenoid sarcoidosis. We report a case of a 43-year-old woman presenting with skin-colored pruritic papules, slightly scaling in trunk, extremities, and ears. These symptoms condition continued to expand and worsen for several years. The patient was otherwise in good health with no lymphadenopathies. Histopathologic examination of a skin biopsy showed an upper dermal granulomatous infiltrate of epithelioid cells, without necrosis, distributed in a lichenoid pattern with many cytoid bodies. We consider this may be the first case presenting a characteristic microscopic granulomatous lichen-like pattern in the setting of a clinically lichenoid type of sarcoidosis.