Paradoxical Eczematous Reaction in a Patient With IL-17 Inhibitor-Treated Psoriasis Vulgaris.

Psoriasis is a chronic dermatologic condition that oftentimes requires extensive trial and error with various topical and systemic therapies until improvement is achieved. Interleukin-17 inhibitors (IL-17i), such as secukinumab, have been utilized in the treatment of psoriasis due to their mechanism of action. As with all medications, IL-17 inhibitors possess adverse effects, the most common being infection, nasopharyngitis, and injection site reaction. However, one rare adverse event, the paradoxical eczematous reaction, has been known to occur among patients on biologics including IL-17 inhibitors. Although it is a rare occurrence, our paper stresses the importance of educating patients about this potential side effect, the benefits and risks of starting a biologic, and obtaining informed consent from the patient. We present a case of a 14-year-old male with recalcitrant psoriasis vulgaris who developed a paradoxical eczematous reaction while undergoing treatment with secukinumab.

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.

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.

Diffuse dermal angiomatosis.

Diffuse dermal angiomatosis (DDA) is a benign and rare acquired, cutaneous, reactive, vascular disorder. We report a rare case of a 43-year-old man who presented with a large (15-cm diameter), indurated, hyperpigmented plaque covering the left buttock for 6 years. This report further discusses DDA with a review of the literature, including its classification, epidemiology, pathophysiology, etiology, histopathology, differential diagnosis, and current therapeutic approaches.

A unique case of pressure-induced alopecia following EEG monitoring.

We report a unique case of pressure-induced alopecia (PIA) in a 11-year-old boy following the use of electroencephalogram (EEG) electrodes on the scalp for 4 days. PIA is caused by localized ischemia leading to vascular congestion and discrete, often circumscribed patches of hair loss within 3-28 days of pressure interface. The synchronous conversion of follicles from anagen to catagen or telogen phase is the most distinctive finding of PIA. PIA is a nonscarring alopecia which often resolves over time without treatment.

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.

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.

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.

Fractional Ablative Laser Followed by Transdermal Acoustic Pressure Wave Device to Enhance the Drug Delivery of Aminolevulinic Acid: In Vivo Fluorescence Microscopy Study.

BACKGROUND: Topical drug delivery is the foundation of all dermatological therapy. Laser-assisted drug delivery (LAD) using fractional ablative laser is an evolving modality that may allow for a greater precise depth of penetration by existing topical medications, as well as more efficient transcutaneous delivery of large drug molecules. Additional studies need to be performed using energy-driven methods that may enhance drug delivery in a synergistic manner. Processes such as iontophoresis, electroporation, sonophoresis, and the use of photomechanical waves aid in penetration. This study evaluated in vivo if there is increased efficacy of fractional CO2 ablative laser with immediate acoustic pressure wave device. METHODS: Five patients were treated and biopsied at 4 treatment sites: 1) topically applied aminolevulinic acid (ALA) alone; 2) fractional ablative CO2 laser and topical ALA alone; 3) fractional ablative CO2 laser and transdermal acoustic pressure wave device delivery system; and 4) topical ALA with transdermal delivery system. The comparison of the difference in the magnitude of diffusion with both lateral spread of ALA and depth diffusion of ALA was measured by fluorescence microscopy. RESULTS: For fractional ablative CO2 laser, ALA, and transdermal acoustic pressure wave device, the protoporphyrin IX lateral fluorescence was 0.024 mm on average vs 0.0084 mm for fractional ablative CO2 laser and ALA alone. The diffusion for the acoustic pressure wave device was an order of magnitude greater. CONCLUSION: We found that our combined approach of fractional ablative CO2 laser paired with the transdermal acoustic pressure wave device increased the depth of penetration of ALA.

Pseudoporphyria: discussion of etiologic agents.

Pseudoporphyria describes a photodistributed bullous disorder with negative urinary, fecal, and serum porphyrin studies. Although pseudoporphyria is thought to be extremely rare (less than 100 reported cases4-5), we propose that this entity is underreported. One author (KB) has seen four cases of pseudoporphyria in the past four years. We describe a patient with nonpruritic, nonpainful bulla on the dorsum of his hands. Biopsy revealed a split at the dermal-epidermal junction; laboratory tests and urinary porphyrin evaluation were negative.

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.