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. Sarcoidal granulomas often stain positive for reticulin fibers, which could be used to distinguish them from the infectious kind. This case should alert clinicians to the fact that the presence or quantity of intact reticular fibers may not be a reliable tool to differentiate between a sarcoidal and an infectious granuloma. Our case also highlights the diagnostic challenge of cutaneous MAC infection.

An atypical presentation of human monkeypox infection with clinicopathologic correlation.

There is growing evidence to support new modes of transmission for human monkeypox infection. As these methods are being explored, this report delineates the day-to-day clinical sequelae following the initial exposure in an HIV-positive man who had sexual intercourse with another man days preceding his infection. We describe atypical cutaneous manifestations involving widespread erythematous pustules with preceding anogenital ulcerations and concomitant bilateral inguinal lymphadenopathy. Clinicopathologic correlation is used to assist in the workup and establishing the diagnosis. Our case supports others reported in the literature that suggest sexual contact as a means of transmission. More research is needed that investigates the presence of infection in both men and women, including those who could act as carriers, to elucidate other pathways in this evolving yet evasive viral disease.

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. Dermatitis herpetiformis (DH) is a chronic recurrent vesicular dermatitis associated with gluten hypersensitivity and also characterized by a neutrophilic infiltrate and granular immunoglobulin A deposits in papillary dermis. MATERIALS AND METHODS: We selected 31 formalin-fixed paraffin-embedded skin specimens of DH that demonstrated typical immunopathologic findings and probed them with rabbit polyclonal immunoglobulinG antielafin antibodies through standard immunohistochemistry analysis. Negative controls consisted of normal skin from elbow and knee surgical re-excisions specimen lacking residual tumor. Positive controls included skin biopsies of active plaque psoriasis, Sweet syndrome, and pyoderma gangrenosum. RESULTS: Similar to what has been previously reported in intestinal sampling of patients with active CD, abnormal expression of elafin was noted in virtually all probed skin biopsies of DH patients with active cutaneous disease. CONCLUSION: Under normal circumstances, keratinocytes overexpress elafin to downregulate a neutrophil mediated inflammatory response. The deficient expression of elafin in the aforementioned probed DH specimens correlates with previous similar elafin underexpression in intestinal samples of active CD. These histological findings suggest that these 2 gluten mediated disorders carry an abnormal elafin underexpression during disease activity.

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. RESULTS: The typical lesion follows a very distinctive clinical and histopathologic evolution over 48 hours, with the formation of a subepidermal pustule overlying a wedge-shaped area of dermal collagen basophilic degeneration with scattered neutrophils. In the 6 cases retrieved from our files, the main features were a superficial and deep dermal, perivascular, periadnexal and interstitial infiltrate consisting of neutrophils, with basophilic degeneration of the collagen. A subepidermal pustule was noted in half of the cases. CONCLUSIONS: In biopsies taken in a clinical setting, even in the absence of the characteristic subepidermal pustule, the diagnosis of imported fire ant sting can be suspected if there is a superficial and deep perivascular, periadnexal and interstitial infiltrate composed of neutrophils, with some basophilic denaturation of collagen.

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. Epidermal consumption has not been previously reported in nonmelanocytic tumors and it is uncertain whether this atypical histologic feature represents a sign of malignant behavior in this rare tumor.

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. We present a case of subacute radiodermatitis stemming from prolonged fluoroscopic exposure during angiography; the lesion appeared only at the site of contact for the ground plate, remote from the field of radiation.

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. It is focal, superficial, and predominantly folliculocentric. It may resemble other tumors such as squamous cell carcinoma and may appear in sections where BCC is absent. The recognition of this entity may help dermatopathologists avoid misdiagnosing this process as a tumor and can suggest further search (section through the block or rebiopsy) when this reactive phenomenon is seen in sections without the associated BCC.

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. This case further supports the lack of association of MTS with RASD.

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. Here, we present a case of LE-LP overlap syndrome in a patient with long standing systemic lupus erythematosus initially misdiagnosed as squamous cell carcinoma.

Drug-induced, Ro/SSA-positive cutaneous lupus erythematosus.

OBJECTIVE: To study the clinical and immunopathologic findings of drug-induced, Ro/SSA-positive cutaneous lupus erythematosus (CLE). DESIGN: Retrospective medical and laboratory record review. SETTING: Immunodermatology Division of Johns Hopkins Hospital (Baltimore, Md). PATIENTS: Of 120 patients found to have anti-Ro/SSA antibodies by hemagglutination and/or double immunodiffusion, 70 had clinical and immunopathologic confirmation of CLE. Fifteen of these 70 patients had a history of new drug exposure, defined as less than 6 months, associated with disease development. RESULTS: The disease-associated drugs included hydrochlorothiazide (5 patients), angiotensin-converting enzyme inhibitors (3 patients), calcium channel blockers (3 patients), interferons (2 patients), and statins (2 patients). The most common presentations were photodistributed diffuse erythema and subacute CLE-type lesions without evidence of significant systemic disease. All specimens revealed interface dermatitis and fine granular IgG deposition along the basement membrane zone and throughout the epidermis. Most patients experienced improvement or resolution of clinical lesions within 8 weeks and decrease of Ro/SSA titers within 8 months after discontinuation of drug treatment. CONCLUSIONS: Antihypertensive drugs are the most commonly associated with Ro-positive CLE. Clinical and immunopathologic features of this drug-induced variant do not seem to differ from the idiopathic disease. In most cases, the disease improves or resolves on discontinuation of the offending drug treatment. It is not known if these drugs precipitate disease in patients who have subclinical disease. Drug-induced Ro/SSA-positive CLE should be included on the differential diagnosis in patients presenting with photosensitive or subacute CLE-type eruptions.

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. RESULTS: A significant acceleration in the development of cutaneous neoplasms was observed in mice that had been exposed to the stressor. The first tumor appeared in the group after 8 weeks, whereas nonstressed mice began to develop these by week 21. CONCLUSION: These results suggest that stress plays a role in potentiating cutaneous carcinogenesis.

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. OBSERVATION: We studied 3 patients with severe and chronic mucosal dominant pemphigus vulgaris (PV). In addition to anti-desmoglein 3 antibodies, these patients had anti-DP autoantibodies, demonstrable by immunofluorescence (IF), immunoprecipitation (IP), and indirect immunoelectromicroscopy (IIEM). This finding suggested these patients may have had PNP and not PV. However, antibodies against periplakin, envoplakin, bullous pemphigoid antigen 1 (BPAG 1), plectin, and 170 kd PNP antigen could not be detected using IP and immunoblotting. Extensive and repeated investigations for an underlying neoplasm throughout the follow-up period were consistently negative for all patients. CONCLUSION: This study demonstrates that anti-DP antibodies without the presence of any other anti-plakin antibodies are not specific for PNP, and are present in some cases of PV. Cellular disadhesion induced by anti-desmoglein antibodies can trigger an epitope-spreading phenomenon with a secondary formation of autoantibodies against desmoplakins, intracellular desmosomal antigens. The role of anti-DP antibodies in the pathogenesis of these PV patients is still unclear. The presence of anti-DP antibodies will produce a false positive serologic interpretation for the diagnosis of PNP especially if one uses only indirect IF on murine bladder, the most commonly employed screening test to identify PNP. More specific immunologic tests are required in this subset of patients with PV.

Neutrophilic dermatosis of the dorsal hand.

Neutrophilic dermatosis of the dorsal hands (NDDH) was originally described as pustular vasculitis (PV) of the hands. Recent debate focuses on categorizing this disorder in the family of neutrophilic dermatoses (ND), as opposed to a primary vasculitis. We present a case of NDDH with clinical and histologic features consistent with ND, and discuss the major concerns for this disease's reclassification.