Combined utility of p16 and BRAF V600E in the evaluation of spitzoid tumors: Superiority to PRAME and correlation with FISH.

BACKGROUND: Spitzoid melanocytic neoplasms are diagnostically challenging; criteria for malignancy continue to evolve. The ability to predict chromosomal abnormalities with immunohistochemistry (IHC) could help select cases requiring chromosomal evaluation. METHODS: Fluorescence in situ hybridization (FISH)-tested spitzoid neoplasms at our institution (2013-2021) were reviewed. p16, BRAF V600E, and preferentially expressed antigen in melanoma (PRAME) IHC results were correlated with FISH. RESULTS: A total of 174 cases (1.9F:1M, median age 28 years; range, 5 months-74 years) were included; final diagnoses: Spitz nevus (11%), atypical Spitz tumor (47%), spitzoid dysplastic nevus (9%), and spitzoid melanoma (32%). Sixty (34%) were FISH positive, most commonly with absolute 6p25 gain (RREB1 > 2). Dermal mitotic count was the only clinicopathologic predictor of FISH. Among IHC-stained cases, p16 was lost in 55 of 134 cases (41%); loss correlated with FISH positive (p < 0.001, Fisher exact test). BRAF V600E (14/88, 16%) and PRAME (15/56, 27%) expression did not correlate with FISH alone (p = 0.242 and p = 0.359, respectively, Fisher exact test). When examined together, however, p16-retained/BRAF V600E-negative lesions had low FISH-positive rates (5/37, 14%; 4/37, 11% not counting isolated MYB loss); all other marker combinations had high rates (56%-75% of cases; p < 0.001). CONCLUSIONS: p16/BRAF V600E IHC predicts FISH results. "Low-risk" lesions (p16+ /BRAF V600E- ) uncommonly have meaningful FISH abnormalities (11%). PRAME may have limited utility in this setting.

Cutaneous symplastic hemangioma: A series of four cases.

Symplastic hemangiomas (SH) are benign vascular lesions that show atypia in vascular smooth muscle and interstitial cells with sparing of endothelial cells. We present four cases of this rare tumor. The patients (two males; two females) ranged in age from 57 to 83 years (median 74); lesions were located on the leg (n = 3) and back (n = 1), and ranged from 6 to 8 mm. SH were well-circumscribed and dermal-based, often with an epidermal collarette (3/4). They were characterized by the presence of variably atypical, hyperchromatic/pleomorphic epithelioid to spindled cells within vascular walls (3/4) and/or perivascular stroma (4/4). Atypical multinucleated cells were present in three of four cases. The overall mitotic rate was low (0-2 mitotic figures per 10 HPFs; mean 0.75 per 10 HPFs), but atypical mitotic figures were seen in two of four cases. Atypical cells were negative for SMA (0/2), desmin (0/2), AE1/3 (0/2), and CAM5.2 (0/1). ERG, CD31, and CD34 stains were positive in endothelial cells but negative in atypical cells (4/4). Lesional cells and vessels were negative for podoplanin (3/3). Symplastic hemangioma is a benign tumor with bizarre atypia that may be mistaken for malignancy. We present four cases of this rare entity to increase awareness of this tumor and discuss the differential diagnosis.

Seronegative dermatomyositis presenting with features of anti-MDA5 subtype.

Dermatomyositis is a chronic inflammatory disorder of muscles and skin, presenting with muscle weakness, characteristic rash, and classic serology findings. Histologically, cutaneous lesions show interface dermatitis with mild perivascular lymphocytic infiltrate and increased intradermal mucin. These findings are non-specific, and the diagnosis is based on clinicopathologic correlation and serology results. However, variation in clinical presentation, serology, and histology can make the diagnosis difficult and requires cognizance of uncommon findings that may serve as a clue to the diagnosis. Herein, we report such a case with unusual histologic features of vascular damage and deep dermal necrosis in a seronegative patient who presented with clinical features of anti-MDA5 variant of dermatomyositis.

Treatment of extensive chronic graft-versus-host disease with extracorporeal photochemotherapy.

Extracorporeal photochemotherapy (ECP; photopheresis), an immunomodulatory therapy developed for cutaneous T-cell lymphoma, has shown promise in treating chronic graft-versus-host disease (cGvHD) in uncontrolled studies. The purpose of this study was to further examine the effects of ECP on cGvHD. ECP (administered initially 3 times weekly on alternating days) was retrospectively evaluated in 14 patients with extensive cGvHD following allogeneic hematopoietic stem cell transplantation. The median time from transplantation to ECP initiation was 29 months (range, 5-96 months). The median number of concomitant baseline treatments per patient was 3 (range, 0-5). During a median ECP duration of 17 months (range, 3-44 months), 3 patients (21%) achieved a complete cutaneous response (100% improvement), 4 patients (29%) achieved a partial cutaneous response (> or =50% improvement), and 7 patients (50%) had stable skin disease. The median time to response was 6 months (range, 2-15 months), and the median response duration was 5 months (range, 1-31 months). At endpoint, responses were ongoing in 4 patients. Resolution or improvement was noted in arthralgia (5/7 patients), oral changes (3/7), elevated liver enzymes (3/5), dry eyes (2/5), joint stiffness (3/3), pulmonary disease (1/3), and thrombocytopenia (1/1). Because of a favorable response, 11 of 13 patients (85%) who received prednisone at baseline were able to taper (7/13; 54%) or discontinue (4/13; 31%) this medication, and 12 of 14 patients (86%) were able to taper (11/14; 79%) or discontinue (1/14; 7%) ECP. Five-year posttransplantation survival was 77%. Our results suggest that adjunctive ECP improves cutaneous and extracutaneous manifestations of cGvHD and has a steroid-sparing effect.