Microreticular perineurioma: A new morphological subtype of a rare entity.

Perineurioma is a benign peripheral nerve sheath tumor. Several subtypes have been described, including plexiform, reticular, and sclerosing. The reticular variant has been previously described as having a net or lace-like growth pattern consisting of large anastomosing cords of spindle-shaped cells. We report a case of an 11-year-old male who presented with a 2-year history of a slowly enlarging, tan-white lesion on the finger. Microscopically, the lesion consisted of cells with ovoid nuclei and delicate, elongate cytoplasmic processes, arranged in a microreticular pattern. The lesional cells were markedly positive for epithelial membrane antigen and claudin-1. Based on these features and the unusual morphology, the case was called a microreticular perineuroma. The patient underwent complete excision of the lesion with no recurrence 9 months after follow-up. To our knowledge, this is the first reported case of this morphologic variant. Awareness of this entity is important to avoid inappropriate management.

Acroangiodermatitis presenting as unilateral hypertrophic verrucous plaques.

Acroangiodermatitis (AAD)[KL1] is a rare vasoproliferative disorder often involving the extremities that has been classified into two variants. Mali-type AAD is more common and associated with chronic venous stasis. Stewart-Bluefarb syndrome[KL2], the other variant, is associated with underlying arteriovenous abnormalities. Mali-type AAD is a relatively benign diagnosis but it may mimic more harmful etiologies such as Kaposi sarcoma both clinically and histologically. A 67-year-old woman with a history of varicose veins, deep vein thrombosis, stroke, and obesity presented to our outpatient clinic with verrucous red-brown papules and plaques on her right lower extremity worsening for three years. Biopsy was consistent with a diagnosis of Mali-type AAD. Providers should be aware of AAD and its variants to accurately differentiate it from more harmful entities.

Application of least absolute shrinkage and selection operator logistic regression for the histopathological comparison of chondrodermatitis nodularis helicis and hyperplastic actinic keratosis.

BACKGROUND: The distinction between chondrodermatitis nodularis helicis (CNH) and hyperplastic actinic keratosis (HAK) on the ear can pose a diagnostic challenge. We aimed to identify histopathological characteristics that could distinguish between CNH and HAK on routine sections using penalized least absolute shrinkage and selection operator (LASSO) logistic regression analysis. METHODS: Cases of CNH (n = 80) and HAK (n = 28) were analyzed for selected histopathological characteristics. Fisher's exact test and LASSO regression were performed. RESULTS: In univariate analyses, the following were significantly associated with CNH: ulceration, acanthosis, granular layer in the majority of the lesion, hypergranulosis at the periphery of the lesion, hyperkeratosis at the periphery of the lesion, hyperparakeratosis at the periphery of the lesion, fibrosis, increased blood vessels, vertically oriented blood vessels, and fibrin. A LASSO model excluding atypia found that fibrin, fibrosis, presence of granular layer, ulceration, and vertically oriented blood vessels were most predictive of CNH. Keratinized strap cells were not a significant predictor. CONCLUSION: We have identified features that may aid in differentiating these entities and demonstrated that a LASSO regression model can identify predictors that may improve diagnostic accuracy. Our results indicate that the highest diagnostic accuracy in this dilemma is dependent on obtaining biopsy specimens with visible dermis.

Hydroxyurea-induced hyperpigmentation with iron deposition.

Hydroxyurea is a chemotherapeutic agent that is used in the treatment of various hematological diseases including chronic myelogenous leukemia, polycythemia vera, and sickle cell anemia. Hydroxyurea is also used to treat psoriasis. Drug-induced hyperpigmentation is a known cutaneous side effect of hydroxyurea along with xerosis, dermal ulcers, and dermatomyositis-like eruptions. Hyperpigmentation has been observed in the oral mucosa, nails, and in a generalized or a diffuse pattern. The mechanism of hyperpigmentation related to hydroxyurea is believed to be correlated with increased melanin. Classically, clinical types of diffuse hyperpigmentation owing to iron deposition in the dermis have been associated with minocycline and not with hydroxyurea. We report a novel case in which hydroxyurea hyperpigmentation is associated with iron deposition.

Filiform Verrucous Sarcoidosis of the Face: A Warty Report.

Sarcoidosis is a multisystem inflammatory condition of unknown etiology. Variability in the cutaneous features of sarcoidosis is profound, and its protean manifestations affirm the condition's designation as one of dermatology's "great mimics." Cutaneous phenotypes of sarcoidosis include but are by no means limited to ichthyosiform, alopecic, erythrodermic, angiolupoid, and verrucous variants. Verrucous sarcoidosis is an exceedingly rare manifestation, and previous reports of this phenotype are limited to 15 cases. Most cases in the extant literature presented on the extremities, with clinical features mimicking that of a common wart, or as verrucous crateriform nodules, ulcers, or cutaneous horns. Only 4 previous reports of facial verrucous sarcoidosis exist in the literature, and to our knowledge, no prior cases have demonstrated filiform lesion morphology. Here we present a case of filiform verrucous sarcoidosis in an otherwise healthy, middle-aged African American man, devoid of internal organ involvement and limited to the face, histopathologically confirmed by the presence of characteristic granulomata devoid of lymphocytic infiltrates.

A Bullous Flare of a Hyperkeratotic Affair: A Case Report.

BACKGROUND: Darier's disease is an autosomal dominant genodermatosis typified by hyperkeratotic papules and plaques in a predominately seborrheic distribution. The vesiculo-bullous variant of Darier's disease is rare. Several previously reported cases have demonstrated clinical and microscopic features resembling familial benign chronic pemphigus or Hailey-Hailey disease. OBJECTIVES: The objective of this report is to describe an uncommon presentation of Darier's disease, which has been infrequently described in the literature. METHODS: The authors present a case of bullous flare of long-standing Darier's disease. CONCLUSIONS: Darier's disease may assume several atypical morphologies, including vesiculo-bullous lesions.