Clinical, histopathologic, immunohistochemical, and electron microscopic findings in cutaneous monkeypox: A multicenter retrospective case series in Spain.

BACKGROUND: The worldwide outbreak of monkeypox has evidenced the usefulness of the dermatologic manifestations for its diagnosis. OBJECTIVE: To describe the histopathologic and immunohistochemical findings of monkeypox cutaneous lesions. METHODS: This is a retrospective histopathologic and immunohistochemical study of 20 patients with positive Monkeypox virus DNA polymerase chain reaction and immunohistochemical positivity for Vaccinia virus in cutaneous lesions. Four cases were also examined by electron microscopy. RESULTS: The most characteristic histopathologic findings consisted of full-thickness epidermal necrosis with hyperplasia and keratinocytic ballooning at the edges. In some cases, the outer root sheath of the hair follicle and the sebaceous gland epithelium were affected. Intraepithelial cytoplasmic inclusion bodies and scattered multinucleated keratinocytes were occasionally found. Immunohistochemically, strong positivity with anti-Vaccinia virus antibody was seen in the cytoplasm of ballooned keratinocytes. Electron microscopy study demonstrated numerous viral particles of monkeypox in affected keratinocytes. LIMITATIONS: Small sample size. Electron microscopic study was only performed in 4 cases. CONCLUSION: Epidermal necrosis and keratinocytic ballooning are the most constant histopathologic findings. Immunohistochemical positivity for Vaccinia virus was mostly detected in the cytoplasm of the ballooned keratinocytes. These findings support the usefulness of histopathologic and immunohistochemical studies of cutaneous lesions for diagnosis of monkeypox.

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.

Eyelid Eccrine Poroma: A Case Report and Literature Review.

Eccrine poroma is a rare benign adnexal tumor arising from intradermal cells of eccrine sweat ducts. At least two-thirds of eccrine poromas present on the extremities, most commonly on the palms and soles. They are scarcely found on the face; to date, only 11 cases of eyelid poromas have been reported in PubMed. Biopsy excision with a free margin is necessary to distinguish it from malignant lesions and avoid recurrence with possible transformation to porocarcinoma. We present the case of a 23-year-old male with a histopathological confirmation of poroma using staining with hematoxylin-eosin on the eyelid, previously clinically diagnosed with molluscum contagiosum. After four years, he has not experienced a recurrence.

Vulvar pseudoverrucous papules and nodules secondary to a urethral--vaginal fistula.

Irritant contact dermatitis is a common cause of genital eruptions representing at least one-fifth of presenting anogenital symptoms. A spectrum of inflammatory reactions have been identified, some of them with features severely mimicking more serious dermatoses, which may lead unnecessary workup and treatments. We report a case of a 10-year-old girl who presented at birth with cloacal atresia involving the rectum and the urethra. A diverting colostomy and a urethral-vaginal fistula were created to correct the deformity. Physical examination reveals numerous shiny, white-gray, pseudoverrucous papules and nodules coalescing into plaques over the vulva and its surrounding skin. Histological examination showed psoriasiform epidermal hyperplasia with a marked reactive acanthosis and altered cornification with parakeratosis, hypogranulosis, and pale keratinocytes in the upper reaches of the epidermis. The lesions regress when the irritating factor was removed. This case represents a peculiar form of presentation of perianal pseudoverrucous papules and nodules, usually secondary to urinary incontinence or encopresis (inability to control the elimination of stool) after surgery for Hirschsprung disease. Because similar findings have not been previously observed in patients with urethral-vaginal fistula, we attempt to extend the spectrum of presentations for a better knowledge of this condition.

Conjunctival Tarsal Actinic Keratosis Treated with Interferon Alfa-2b: A Rare Case Report and Literature Review.

Conjunctival neoplasia is one of the most frequent tumors in the eye. Actinic keratosis (AK) or solar keratosis is a precancerous lesion that is included with other epithelial tumors. This alteration does not break the basal membrane. There is enough evidence of successful outcomes to consider interferon alfa-2b (IFN alfa-2b) as the first choice of treatment for this type of tumors. In addition, side effects are mild and uncommon. We report a case in an 83-year-old woman who was referred to evaluate a leukoplakia in the tarsal conjunctiva of the lower left eyelid that measured 1 cm in diameter. Pathological study revealed AK. After the INF alfa-2b treatment, we observed conjunctival hyperemia, noninfiltrated upper nasal de-epithelization, and inferior nasal bulla. AK with presentation in conjunctiva is rarely described and in tarsal conjunctiva is exceptional. It is the first case published with only tarsal conjunctiva affectation.

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.

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.

Clinicopathological study of 21 cases of eyelid actinic keratosis.

BACKGROUND: Actinic keratosis (AK) is an intraepidermal malignancy precursor form of cutaneous squamous cell carcinoma (SCC), which generally occurs in fair-skinned individuals with long-term sun exposure. We present a case series of AKs on the eyelid. METHODS: This was a retrospective study. Data of patients seen from 1994 to 2005 were used in the analyses. RESULTS: There were 21 cases of eyelid AKs in 18 patients, 11 men, and seven women, with a mean age of 70 (range 43-80) years. Most tumors were located on the upper eyelid. The mean size was 0.8 +/- 0.4 cm. The most frequent AK type was type I (76.2%). Men had bigger lesions and more frequent free-margin eyelid involvement. CONCLUSIONS: In our series, tumors were more frequent and had worse clinical and histopathological features in men. AKs are closely related to SCC and need to be removed before they turn into SCC. They can be safely and effectively removed, and therapy is therefore warranted.

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.