TRPS1 expression in breast angiosarcoma.

Angiosarcoma (AS) of the breast, a rare mesenchymal neoplasm, exhibits distinct forms based on etiological and genetic features. While cases with typical clinical presentation and morphology allow for a straightforward diagnosis, challenges arise when clinical data are scarce, diagnostic material is limited, or morphological characteristics overlap with other tumors, including undifferentiated carcinomas. The trichorhinophalangeal syndrome protein 1 (TRPS1), once regarded as highly specific for breast carcinomas, now faces doubts regarding its reliability. This study explores TRPS1 expression in breast AS. Our investigation revealed that 60% of AS cases displayed TRPS1 labeling, contrasting with the 40% lacking expression. Scoring by four independent readers established a consensus, designating 12/35 ASs as unequivocally TRPS1-positive. However, uncertainty surrounded nine further cases due to a lack of reader agreement (being substantial as reflected by a kappa value of 0.76). These findings challenge the perceived specificity of TRPS1, shedding light on its presence in a noteworthy proportion of breast ASs. Consequently, the study underscores the importance of a comprehensive approach in evaluating breast ASs and expands the range of entities within the differential diagnosis associated with TRPS1 labeling.

Cutaneous metastases at the sites of pembrolizumab-induced bullous pemphigoid lesions in a patient with melanoma.

The authors report a case of bullous pemphigoid (BP) that occurred during pembrolizumab therapy in a 67-year-old male patient with advanced melanoma. Following regression of BP blisters, they reintroduced anti-PD-1 treatment. Due to the flare-up of BP, immunotherapy was discontinued again and corticosteroid was restarted. As the BP lesions regressed, interestingly, new skin metastases developed, exactly where the blisters were. One year after discontinuation of anti-PD-1 treatment, considering the significant tumor progression, pembrolizumab was restarted. This induced tumor remission, while the added low-dose corticosteroid was able to prevent the recurrence of BP. The patient carries the BP-predisposing HLA-DQB1*03:01 allele. In conclusion, anti-PD-1 rechallenge may be considered in metastatic melanoma, even if restarting anti-PD-1 has previously caused the flare-up of BP symptoms.

Immune checkpoint inhibitors prolong the survival of patients with metastatic melanoma. Bullous pemphigoid (BP) is a rare, cutaneous, immune-related adverse event. The authors report a case of BP that occurred during pembrolizumab therapy in a 67-year-old male patient with advanced melanoma who responded to anti-PD-1 treatment with a partial response. Following the resolution of BP symptoms, pembrolizumab treatment was restarted after discontinuation of systemic corticosteroid therapy. Due to the flare-up of BP, anti-PD-1 treatment was discontinued and steroid therapy was restarted; however, skin metastases soon developed, exactly where the BP blisters were. Pembrolizumab rechallenge was successful in inducing the complete regression of skin metastases, while the added low-dose corticosteroid was able to prevent the recurrence of BP.

First Glance of Molecular Profile of Atypical Cellular Angiofibroma/Cellular Angiofibroma with Sarcomatous Transformation by Next Generation Sequencing.

Cellular angiofibroma is a rare benign mesenchymal neoplasm most commonly occurring in the vulvovaginal region in women and the inguinoscrotal region in men with specific genetic deletion involved in the RB1 gene in chromosome 13q14 region. Atypical cellular angiofibroma and cellular angiofibroma with sarcomatous transformation are recently described variants showing worrisome morphological features and strong, diffuse p16 expression. Nevertheless, the molecular profile of these tumor entities is largely unknown. We carried out a next generation sequencing (NGS) study from six cases of atypical cellular angiofibroma and cellular angiofibroma with sarcomatous transformation. We were able to identify oncogenic TP53 gene mutations (33%) which may contribute to pathogenesis also resulting in p16 overexpression. In addition, RB1 gene alterations generally present were identified. Since it is a recently described and rare entity, the whole molecular signaling pathway is still largely obscured and the analysis of larger cohorts is needed to elucidate this issue.

Paravertebral Low-grade Fibromyxoid Sarcoma with Supernumerary Ring Chromosome: Case Report and Literature Review.

Low-grade fibromyxoid sarcoma (LGFMS) is a rare soft-tissue neoplasm with a deceptively benign histological appearance and low-grade malignant potential which is often mistaken for other reactive or benign lesions. It most frequently harbors balanced t(7;16) translocation, and leads to the fusion of the FUS and CREB3L2 genes which can be detected by cytogenetic methods. Young adults are most commonly affected and it typically arises in the deep proximal extremities or trunk with frequent recurrences. It may metastasize to the lungs several years later. Paravertebral LGFMS is exceedingly rare and only few cases have been published in the literature. In those cases the novel immunohistochemical markers and cytogenetic studies were not performed and morphological mimickers could not be confidently excluded.We present a rare case of paravertebral LGFMS from a 54-years-old male patient, which previously was misdiagnosed as a neurofibroma with subsequent tumor recurrence. The concrete diagnosis was established by using MUC4 immunohistochemical stain and fluorescent in situ hybridization (FISH), which showed diffuse membranous positivity and supernumerary ring chromosome with unbalanced FUS gene rearrangement, respectively. The latter finding is also rare and may cause diagnostic dilemma if one is not aware of such uncommon, but well-documented phenomenon. Differential diagnosis with other low-grade spindle cell tumors will also be discussed along with the literature review.