Conjunctival keratoacanthoma: a clinical and histopathological case series.

OBJECTIVE: To present a series of conjunctival keratoacanthomas and provide clinical, histopathological, immunohistochemical, and imaging results that characterize this rare entity. METHODS: A retrospective chart review of records from 2005 to 2023 from the Florida Lions Ocular Pathology Laboratory was conducted. Nine patients with histologically proven conjunctival keratoacanthoma were identified. Data extracted includes demographics, clinical history, diagnostic testing, histopathological and immunohistochemical testing, treatment modalities, and recurrences. RESULTS: Patients' mean age was 55.2 ± 21.1 years (range: 22-83). 77.8% (7/9) of patients were male. 55.6% (5/9) were Hispanic. 55.6% of lesions (5/9) were in right eyes. 55.6% of lesions (5/9) were on the temporal, bulbar conjunctiva. The lesions were rapidly growing, with mean onset time of 4.71 ± 3.30 weeks (range: 2-12). High-resolution anterior segment optical coherence tomography of three lesions revealed hyper-reflective, thickened epithelium with abrupt transition between normal and abnormal epithelium. Underlying disorganized subepithelial tissue was noted. However, the overlying abnormal epithelium caused considerable shadowing, which obscured subepithelial structures. Prominent, keratin-filled, cup-shaped lesions with faulty maturational sequencing that extend full thickness, variably pale cytoplasm, and foci of dyskeratosis and hyperkeratosis were present on all lesions' histopathology. All lesions were surgically excised, but two demonstrated partial spontaneous resolution before surgery. Two patients were lost to follow-up; the remaining seven had no signs of recurrence at a of mean of 36.9 ± 45.4 months (range: 3 to 141 months) of follow-up. CONCLUSIONS: Conjunctival keratoacanthomas are rare lesions of the ocular surface with distinct clinical, histopathologic, and diagnostic features.

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.

Squamoid Eccrine Ductal Carcinoma of the Eyelid: Clinicopathologic Correlation of a Case.

Squamoid eccrine ductal carcinoma (SEDC) is a rare cutaneous neoplasm that often manifests as a plaque or nodule in sun-exposed areas of older patients. Herein, the authors report the first case of SEDC in the eyelid. A 76-year-old man presented with a 2.5 × 1.5 mm area of left upper eyelid erythema, thickening, ulceration, and scaling with madarosis superotemporally just above the lash line. Full-thickness wedge biopsy demonstrated irregular epithelial tubules with nuclear atypia and focal squamous differentiation, consistent with SEDC. The patient underwent Mohs resection and has had no recurrence approximately 27 months after surgical removal. The authors present this case to raise awareness of SEDC to ophthalmologists as all previous cases have been described in the nonophthalmic literature. A full-thickness biopsy is recommended to avoid misdiagnosing SEDC as squamous cell carcinoma (SCC), a less aggressive tumor. With greater awareness, there may be increased recognition of this likely underreported, more malignant entity.

Diagnostic application of cyclin D1 fluorescent in situ hybridization for histologically undetermined early lesions of acral melanoma in situ: A case series.

Histologically undetermined early acral melanoma in situ (HUAMIS) is rare but a diagnostic challenge, being clinically and dermoscopically MIS (late onset, a large size (>7 mm), parallel ridges pattern) but microscopically without recognizable cytological atypia. Cyclin D1 (CCND1) gene amplification is a genetic aberration occurring in the early radial growth phase of AMs and could thus help determine malignancy for this disease. We determine the value of CCND1 amplification by FISH as a diagnostic marker for HUAMIS. CCND1 amplification was examined in paraffin-embedded skin biopsies and excisions using a dual-probes fluorescence in situ hybridization (FISH) (11q13 and CEP11). One FISH-negative case 6 was additionally examined by Mypath Melanoma (qRT-PCR). Seventeen cases (12 dysplastic nevi, 3 AMIS, and 2 invasive AM) were served as negative controls for FISH. All six patients (4 females and 2 males) were Hispanic. Pigment lesions were on the left plantar foot (4), right third finger palm (1), and right thumb subungual (1). All cases showed similar clinical and dermoscopical characteristics, including late onset (50 to 74 years old), long duration (from 2 to 15 years), large-sized pigments (from 16 to 40 mm), and a parallel ridge pattern. Junctional melanocytes with no or minimal atypia from five cases showed CCND1 amplifications. Four of 5 cases were received 1st or/and 2nd wide excisions, which demonstrated foci of histologically overt MIS. One FISH-negative case 6 demonstrated "likely malignancy" scores (>2) by Mypath Melanoma (qRT-PCR). None of negative controls showed the amplification. We propose here a simple CCND1 FISH is a practical diagnostic test to determine the malignancy of the very early progression phase of AM preceding histopathologically defined MIS. Cases presented here could be an indolent subtype of AMIS characterized by carrying a long latent radial growth phase without vertical growth, mimicking lentigo maligna.

What's eating you? blister beetles revisited.

Blister beetles are a group of insects that include the Meloidae, Oedemeridae, and Staphylinidae families. The most well-known family, Meloidae, has more than 200 species known for causing a blistering dermatitis in humans by emitting the substance cantharidin, which has been pharmacologically used as a vesicant and can cause deleterious effects if ingested. Most recently, blister beetles have been studied for their anticancer properties.

Onychomatricoma: A Rare Nail Tumor with an Unusual Clinical Presentation.

First described in 1992, onychomatricoma is a rare, benign, fibroepithelial tumor of the nail matrix with few reported cases in the literature. The tumor predominately affects the fingers of Caucasian women during the 5th decade of life and is typically slow growing and painless. The authors present a unique clinical presentation of a giant onychomatricoma in a darker-skinned 60-year-old South Asian individual who presented with a large dome-shaped nail that was smooth, shiny, and green.

Blue Nevi of the Ocular Surface: Clinical Characteristics, Pathologic Features, and Clinical Course.

PURPOSE: Blue nevus is a melanocytic tumor that is commonly found in the skin. Extracutaneous presentations, including the ocular surface, are rare. As such, the purpose of this study was to characterize the clinical features and clinical course of congenital melanocytic tumor (blue nevus) of the conjunctiva. DESIGN: Retrospective, noncomparative case series. PARTICIPANTS: Twenty-one patients with 23 blue nevi of the ocular surface that were excised surgically between 2000 and 2016. METHODS: Chart review of patients identified from a database search of the Florida Lions Ocular Pathology Laboratory records. Pathologic diagnoses were confirmed by 2 pathologists (S.R.D. and G.E.). All specimens were bleached and, tissue permitting, stained using SOX10 (MilliporeSigma, Darmstadt, Germany) and CD68 (Leica Biosystems, Nussloch, Germany). MAIN OUTCOME MEASURES: Clinical characteristics, pathologic features, and clinical course. RESULTS: Mean age of the population was 55±15 years; 71.4% (n = 15) were white and 57.1% (n = 12) were men. One patient had 3 lesions, for a total of 23 lesions examined. Clinically, 13 lesions were on the bulbar conjunctiva, 3 were on the tarsal conjunctiva, 3 were in the fornix, 2 were caruncular, 1 was episcleral, and 1 was at the limbus. Before excision, 8 patients were thought to have primary acquired melanosis, 4 with concern for primary conjunctival melanoma, and 1 thought to have metastatic disease from a plantar melanoma. Five lesions were thought to be benign, and in 8 patients, the lesions were identified incidentally after other ocular surgeries, with no diagnosis of the lesions before excision. Pathologic features were consistent with simple blue nevi in 21 lesions and cellular blue nevus in 2 lesions. No malignant transformations were noted in any patient over the mean 20.2-month follow-up period (range, 2 weeks-103 months). CONCLUSIONS: Blue nevus is a rare deeply pigmented congenital melanocytic lesion with a benign clinical course that can appear clinically similar to primary acquired melanosis or melanoma.

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.

Giant proliferating trichilemmal cyst arising from a nevus sebaceus growing for 30 years.

Nevus sebaceus of Jadassohn, a congenital cutaneous hamartoma, has the potential to develop into various epidermal adnexal-origin neoplasms. While the most common neoplasms are trichoblastoma or syringocystadenoma, proliferating trichilemmal cysts are exceptionally rare. We report a case of a 63-year-old Cuban male with a giant proliferating trichilemmal cyst arising from a nevus sebaceus on the right shoulder which had been growing for 30 years. Proliferating trichilemmal cysts arising from nevus sebaceus cases are difficult to diagnose clinically and histologically as they are very rare and have not been defined by exact diagnostic criteria. Our case creates awareness of this particular tumor in nevus sebaceus and shares clinical and histological diagnostic information that can be used to make a proper diagnosis.

Dark homogeneous streak dermoscopic pattern correlating with specific KIT mutations in melanoma.

IMPORTANCE: Mutations driving melanoma growth have diagnostic, prognostic, and therapeutic implications. Traditional classification systems do not correlate optimally with underlying melanoma growth-promoting mutations. Our objective was to determine whether unique dermoscopic growth patterns directly correlate with driving mutations. OBSERVATIONS: We evaluated common driving mutations in 4 different dermoscopic patterns (rhomboidal, negative pigmented network, polygonal, and dark homogeneous streaks) of primary cutaneous melanomas; 3 melanomas per pattern were tested. Three of the 4 patterns lacked common mutations in BRAF, NRAS, KIT, GNAQ, and HRAS. One pattern, the dark homogeneous streaks pattern, had unique KIT mutations in the second catalytic domain of KIT in exon 17 for all 3 samples tested. Two tumors with the dark homogeneous streaks pattern turned out to be different primary melanomas from the same patient and had different sequence mutations but had an impact on the same KIT domain. CONCLUSIONS AND RELEVANCE: While future study is required, these results have multiple implications. (1) The underlying melanoma-driving mutations may give rise to specific dermoscopic growth patterns, (2) BRAF/NRAS mutations in early melanomas may not be as common as previously thought, and (3) patients may be predisposed to developing specific driving mutations giving rise to melanomas or nevi of similar growth patterns.

Subcutaneous (deep) fungal infections.

Fungal infection is a common clinical problem in dermatology. While most cases in practice are superficial infections, invasive subcutaneous mycoses are important to recognize and treat, as these conditions often have significant morbidity and mortality. Deep fungi demonstrate species-specific syndromes and may be identified by clinical and histological features in addition to serological evaluation and culture. Identification of the common innoculation subcutaneous mycoses, as well as those associated with pulmonary primary infection and dissemination to the skin is important, as treatments vary by organism and clinical setting. This overview will help to identify the key dermatological presentations of subcutaneous fungal infection, and the clues they give to cause.

Purely cutaneous rosai-dorfman disease with immunohistochemistry.

BACKGROUND: The cutaneous form of Rosai-Dorfman disease (RDD) is a rare entity that manifests solely with skin papules or nodules and does not present with the usual myriad of symptoms of classical RDD. AIMS: To analyze the most recent publications regarding cutaneous RDD to point out updated, relevant aspects regarding future directions for clinical recognition and management. To identify histopathologic and immunohistochemical findings in skin lesions that permit diagnosis. MATERIALS AND METHODS: We present a case of a gentleman with a history of multiple lipomas with a new solitary nodule on physical exam; microscopic examination shows the typical findings of RDD with the associated diagnostic immunohistochemical profile, as well as the expected finding of histiocytes engulfing other intact inflammatory cells. RESULTS: Our patient was managed with surgical excision of the entire lesion, one of the several available treatment options. Long-term follow-up 2 years later did not reveal any complications, recurrences, or new lesions. CONCLUSION: The diagnosis of cutaneous RDD is differentiated from other histiocytic conditions by the combination of clinical findings accompanied by histopathologic and immunohistochemical confirmation.

Atypical form of transient reactive papulotranslucent acrokeratoderma in a cystic fibrosis carrier.

We report the first documented case of an atypical form of transient reactive papulotranslucent acrokeratoderma (TRPA) in a patient heterozygous for the ΔF508 CFTR(cystic fibrosis transmembrane conductance regulator) mutation. TRPA represents a condition that classically presents with translucent to white plaques that become evident after water exposure. An atypical form with persistent lesions has also been described. Our patient is a 16-year-old girl with small, white papules coalescing into pebbly plaques on the palms. This condition is exacerbated after 5-10 min of water exposure and is associated with discomfort. The skin biopsy showed expanded stratum corneum, orthohyperkeratosis and dilation of eccrine ducts consisting with TRPA. A cystic fibrosis carrier state, barrier function defect, hyperhidrosis and the intake of cyclooxygenase inhibitors may have been pathogenic factors in our patient.