Cutaneous Mycobacterium avium-intracellulare infection masquerading as sarcoidosis.

Mycobacterium avium-intracellulare (MAC) infection may have different skin manifestations, including cutaneous granulomas. Granulomatous skin reactions have distinct morphologic and histopathologic appearances. We present the case of an adolescent male with cutaneous MAC, misdiagnosed as sarcoidosis after initial biopsy results, demonstrated preservation of reticulin fibers and absence of organisms within granulomas.

Lupus Erythematosus Lichen Planus Overlap Syndrome Mimicking Squamous Cell Carcinoma.

Lupus erythematosus lichen planus (LE-LP) overlap syndrome remains an uncommon diagnostic entity, combining both the histologic and clinical features of lupus erythematosus and lichen planus. A rare and challenging diagnosis, clinicopathologic correlation is essential for accurate and timely identification. Histologically, superficial evaluation of lupus erythematosus lichen planus overlap syndrome can mimic squamous cell carcinoma due to the presence of squamatized keratinocytes with concomitant irregular acanthosis.

Expression of Elafin in Dermatitis Herpetiformis.

Background: Elafin is a serine protease inhibitor that has various epithelial cell regulatory and immunomodulatory effects including inactivation of neutrophil elastases. This later role originated the interest of elafin in certain neutrophil-rich dermatoses. Interestingly, it has been speculated that elafin has a protective role by slowing the deamidation process of gliadin in celiac disease (CD), despite the typical absence of neutrophils in intestinal histologic samplings.

Melanocytic Matricoma With Consumption of the Epidermis: An Atypical Histologic Attribute or a Malignant Variant?

Melanocytic matricoma is a recently described cutaneous adnexal tumor composed of matrical and supramatrical cells admixed with pigmented dendritic melanocytes, thought to recapitulate the anagen bulb of the hair follicle. We report a case of a 75-year-old white man, which demonstrates consumption of the epidermis that is defined as thinning of the epidermis with attenuation of the basal and suprabasal layers and loss of the normal rete architecture in areas of direct contact with neoplastic cells. It has been associated with aggressive histologic features in melanoma and likely represents an early phase of ulceration due to attenuation.

Imported fire ant envenomation: A clinicopathologic study of a recognizable form of arthropod assault reaction.

Background: Skin reactions to the sting of the imported fire ant have characteristic clinicopathological features.

Methods: One case of experimental envenomation was prospectively followed during 48 hours, with biopsies. In addition, 6 cases from our laboratory were retrospectively evaluated histopathologically for the following features: spongiosis, exocytosis (and type of cells), pustule formation, erosion/ulceration, epidermal necrosis, scale/crust, papillary dermal edema, inflammatory dermal infiltrate (cell type, density, depth, distribution, shape), red blood cell extravasation, vasculopathy and vasculitis.

A unique case of subacute radiodermatitis.

Subacute radiodermatitis is a rare cutaneous disease induced by ionizing radiation. It often is mistaken for contact dermatitis, fixed drug eruption, or connective-tissue disease. Routine use of fluoroscopy has flourished in many types of medical procedures.

Basal cell carcinoma-associated paratumoral follicular and epidermal hyperplasia.

Reactive epithelial hyperplasia is a well-known phenomenon which occurs adjacent to certain neoplasms such as cutaneous fibrous histiocytoma, granular cell tumor, Spitz nevus, and melanoma. We report 46 cases of paratumoral follicular and epidermal hyperplasia associated with basal cell carcinoma (BCC). This reactive process associated with BCC has certain characteristic features.

Reticulated acanthoma with sebaceous differentiation. Lack of association with Muir-Torre syndrome.

We hereby report a case of a reticulated acanthoma with sebaceous differentiation (RASD), a rare and often mislabeled benign lesion that is characterized by epidermal acanthosis and clusters of sebocytes in a reticulated seborrheic keratosis-like pattern. The presence of multiple sebaceous tumors, most notably cystic sebaceous adenomas and keratoacanthomas, has been associated with Muir-Torre syndrome (MTS). Although very rare, cases of RASD have been reported with MTS, which potentially offers profound clinical significance to this neoplasm.

Chronic stress accelerates ultraviolet-induced cutaneous carcinogenesis.

Background: Physical and emotional stressors have been found to mediate a wide variety of biological changes including the facilitation of tumor progression; however most of these paradigms utilized artificial sources of neoplasms and stress.

Methods: Skh mice were exposed to carcinogenic doses of ultraviolet light (UV). The stressed group was subjected to the close proximity of fox urine as a source of stress from the presence of the odor of their natural predator, while the control group remained stress free.

Mucosal dominant pemphigus vulgaris with anti-desmoplakin autoantibodies.

Background: Anti-desmoplakin (DP) antibodies are present in paraneoplastic pemphigus (PNP) as a component of a complex humoral autoimmune reaction characterized by antibodies against proteins of the plakin family, desmogleins, and an unidentified 170 kd protein. Anti-DP antibodies have also been rarely identified in other blistering diseases. The significance of anti-DP antibodies in the pathogenesis of bullous diseases is unclear.