Review of dermatofibrosarcoma protuberans.

The clinical features, histological subtypes and management of dermatofibrosarcoma protuberans (DFSP) are reviewed in this article. DFSP is an uncommon cutaneous sarcoma first described in 1890. It has a high local recurrence rate, low metastatic rate and low mortality. The crude incidence rate in England in 2019 was reported as 3.0 per million person-years. A fusion of platelet-derived growth factor subunit B (PDGFB) and COL1A1, t(17;22)(q22;q13), has been found in over 90% of people with DFSP. This fusion is thought to upregulate PDGFB expression, stimulating cell growth by activation of Ras mitogen-activated protein kinases and PI3K-AKT-mTOR, potentiating oncogenesis. DFSP usually presents as an asymptomatic flesh-coloured, thickened, rubbery plaque or nodule with an uneven surface. The most common sites are the trunk followed by lower limbs, head and neck and upper limbs. Larger tumours can infiltrate underlying local structures and around 1% metastasize. Key histological features in DFSP are spindle cells arranged in a storiform pattern with intense CD34 staining. Histological subtypes include classical DFSP, Bednar, myxoid, giant cell fibroblastoma, atrophic and DFSP-fibrosarcomatous. The gold standard management for localized tumours is surgical: current recommendations favour Mohs micrographic surgery over wide local excision. Adjuvant radiotherapy may be offered after surgery. Imatinib can be used as neoadjuvant therapy and in patients with inoperable or metastatic tumours. Further research should be conducted to better understand pathogenesis of DFSP, identify associated risk factors and standardize management.

Quantitative and Spatial Analysis of CD8+/PD-1 Tumor-Infiltrating Lymphocytes as a Predictive Biomarker for Clinical Response of Melanoma In-Transit Metastases to Topical Immunotherapy.

BACKGROUND: Melanoma in-transit metastases (ITMs) are a challenge to treat and associated with systemic disease and poor prognosis. Topical diphencyprone (DPCP), a potent contact sensitizer, is an established treatment for melanoma ITMs. This exploratory study investigated the utility of BRAF mutation status, CD8, PD-1, PD-L1, and TILs distribution as biomarkers for response of ITMs to topical immunotherapy (DPCP). METHODS: The ITM deposits of 40 patients treated with DPCP were subjected to biomarker analysis for BRAF status, CD8 and PD-1 expression on tumor-infiltrating lymphocytes (TILs), and tumor PD-L1 expression. Response to DPCP and overall survival (OS) were compared by biomarker status. RESULTS: After 12 weeks, 10 patients (25%) had a complete response, 12 patients (30%) had a partial response, and 18 patients (45%) had no response. No significant association was found between any individual biomarker and response to DPCP or OS. The BRAF mutation rate was 25% (10/40). All the patients with a complete response had BRAF wild-type tumor. Peritumoral CD8+ T-cells were associated with complete response (P = 0.041). Both CD8+ and PD-1 expressions were highly correlated (P < 0.0001), and the highest levels of PD-1 expression were detected at the peritumoral interface (P = 0.0004). Only two cases were PD-L1-positive, and both had a complete response to DPCP (P = 0.043). CONCLUSION: Patients who have BRAF wild-type tumor are more likely to experience a complete response to DPCP. Peritumoral TILs and PD-1 expressions may predict a better response to DPCP. Expression of PD-L1 may be associated with a complete response to DPCP. A larger prospective study is required.

Symplastic glomangioma: information review and addition of a new case.

Glomus tumors are neoplasms differentiating toward specialized cells found in the glomus body, a structure involved in thermoregulation. Although the vast majority is benign, the occurrence of malignant glomus tumors is well recognized. Criteria for prediction of malignant potential include a deep location, large size, infiltration, necrosis, and nuclear atypia. Symplastic glomus tumors are benign neoplasms showing striking nuclear pleomorphism in the absence of other malignant criteria. Recognition of this rare morphologic aberration would prevent an inadvertent diagnosis of malignancy.

Is a cystic sebaceous neoplasm always marker for Muir-Torre syndrome?

Cystic sebaceous neoplasms are uncommon and almost always regarded as a consistent marker for Muir-Torre syndrome. We present a 73-year-old man with a cystic sebaceous neoplasm on his arm, clinically not associated with Muir-Torre syndrome.