Urticaria Pigmentosa Without Pruritus.

Mastocytosis is a group of disorders characterized by the pathologic accumulation of mast cells in various tissues. One example of mastocytosis is urticaria pigmentosa, which presents with mastocytomas that can cause hives and, when irritated, pruritus. To our knowledge, we are describing the first case of urticaria pigmentosa without pruritus. The patient had a positive Darier's sign, stated that they never felt itchy, and denied ever using a topical steroid or antihistamine. Although our patient declined additional testing, patients like this may benefit from a detailed evaluation of their sensory system through both quantitative sensory testing and genetic analysis. J Drugs Dermatol. 2024;23(3):     doi:10.36849/JDD.7558e.

Atypical Fibroxanthoma Treated with a Topical Combination of Imiquimod, Tazarotene, and 5-Fluorouracil.

This case report describes an 80-year-old man who presented with a growing erythematous nodule with erosion, measuring 0.6 cm × 0.6 cm, on his right temple. This lesion was later diagnosed as atypical fibroxanthoma (AFX). Instead of undergoing Mohs surgery, the gold standard treatment, the patient opted to pursue a topical treatment regimen because of financial costs associated with surgical removal and repair. This topical regimen consisted of tazarotene cream, imiquimod cream, and 5-fluorouracil solution, applied for 30 days. The patient was directed to use this combination 5 days per week for 6 weeks. The specified dosage for each medication was a fifth of a packet of imiquimod 5% cream, an equivalent amount of tazarotene 0.1% cream, and a single drop of 5-fluorouracil 2% solution. These were combined on a bandage and placed on the lesion overnight. Following the treatment, a 3-week post-application examination revealed an erosion, 1.0 cm × 0.9 cm, amidst erythema. A subsequent incisional biopsy with histopathology and stains for CD10 and CD99, 3 weeks after treatment, and three punch biopsies with histopathology and stains for CD10 and CD99, 1-year post-treatment, confirmed the absence of AFX. AFX is a superficial variant of pleomorphic dermal sarcoma (PDS), which shares histologic similarities, yet the exact relationship between AFX/PDS and undifferentiated pleomorphic sarcoma is still not well understood. Previous studies have indicated a genomic similarity between AFX/PDS and cutaneous squamous cell carcinoma (cSCC), which suggests the potential efficacy of cSCC-targeted treatments for AFX/PDS. This case marks the first recorded instance of successful topical medical treatment of AFX, offering an alternative for patients who may opt out of surgical intervention. Continued research to assess the broader efficacy of this approach is encouraged.

Mycobacterial Spindle Cell Pseudotumor (MSP): A Case Report.

Mycobacterial spindle cell pseudotumor (MSP) is a rare proliferation of spindle-shaped histiocytes that occurs most frequently in lymph nodes but has also been documented in the skin, soft tissue, abdomen, and other sites. These lesions contain acid-fast mycobacteria, most commonly Mycobacterium avium complex. Fewer than 10 cases of cutaneous MSPs have been published, and most have occurred in immunocompromised patients, either due to human immunodeficiency virus (HIV) infection or immunosuppressive medications. The differential diagnosis includes Kaposi's sarcoma and other spindle cell neoplasms, which can be distinguished based on histology and special stains. We present the case of a 76-year-old man with HIV infection who presented with a diffuse rash on his arms and legs. A pretibial biopsy was performed and revealed tubercular MSP.

Keratinocyte Carcinoma Chemoprevention With a Combination of Imiquimod, 5-Fluorouracil, and Tretinoin.

BACKGROUND: The incidence of keratinocyte carcinomas (KCs), comprising basal and squamous cell carcinomas, is rising in the United States. Chemoprevention is one modality by which patients can reduce the incidence of KCs. METHODS: We performed a retrospective review of 327 patients who employed a combination of imiquimod 5% cream, 5-fluorouracil 2% solution, and tretinoin 0.1% cream in a field therapy regimen over the face/ears or scalp for chemoprevention. RESULTS: Patients had dramatically lower odds of having KCs in the treatment location (face/ears or scalp) in the one-year period after field treatment than in the one-year period preceding field treatment (OR=0.06, 95% CI: [0.02, 0.15]). Patients were also at lower odds of having KCs in non-treated areas the year after field treatment than in the year preceding it (OR=0.25, 95% CI: [0.14, 0.42]). Additionally, fewer cryotherapy sessions were performed for actinic keratoses in the treatment areas in the year after treatment (mean=1.5, SD=1.21) than the year preceding treatment (mean=2.3, SD=0.99; t=11.68, P<0.001). CONCLUSIONS: A combination of imiquimod 5% cream, 5-fluorouracil 2% solution, and tretinoin 0.1% cream were effective at reducing the incidence of new KCs for at least one year. Individualized treatment application frequency allowed for increased patient adherence. Prospective studies evaluating combination topical treatments for chemoprevention of KCs are needed to further assess the treatment effects found in this study. J Drugs Dermatol. 2023;22(5): doi:10.36849/JDD.7334.