Dermato

Italian Court of Cassation Ruling Decree 30032 of 30 October 2023 discusses a medical malpractice case concerning the diagnosis of dermatofibrosarcoma protuberans and the alleged diagnostic and therapeutic delay. By examining how the ruling frames the role of histopathology in proving pathology benignity, authors prompt to reflect on diagnostic path, the allocation of the burden of proof, and the role of dermatologist’s expertise in professional liability issues. Over a four-year period, five health professionals were involved in a claim concerning an initial diagnosis of an epidermoid cyst and a subsequent diagnosis of dermatofibrosarcoma protuberans. The plaintiff questioned the delay in diagnosis, and the Court of Cassation found two physicians liable because they could not prove that the treated pathology was initially benign. We argue that equating diagnostic correctness exclusively with histological confirmation is unnecessary, both clinically and legally, in typical cases, if the reasoning and findings are adequately documented. Additionally, we examine the value of dermatologists’ experience and the scope of professional competence as measures of liability. Finally, we outline the minimum standards of clinical documentation necessary to make the diagnostic pathway traceable and verifiable. The diagnostic process is a discretionary effort that integrates multiple sources of information, both instrumental and experiential, to reach the most reasonable hypothesis. While histopathology is a crucial tool, it is not the sole gateway to a correct diagnosis of every cutaneous alteration. Adequate disclosure and structured documentation of the diagnostic reasoning are fundamental to the care process and fair assessment of professional responsibility.

Immune checkpoint inhibitors (ICIs), particularly PD-1/PD-L1 antibodies, have significantly improved outcomes in a variety of solid tumors, including urothelial carcinoma. However, their use is frequently associated with immune-related adverse events (irAEs) which frequently affect the skin and mucous membranes. Among these, plasma-cell-rich infiltrates are exceptionally rare. Circumorificial plasmacytosis (COP) is a rare, predominantly reactive condition typically involving mucosal transition zones, with histologic features characterized by dense, polyclonal plasma cell infiltrates and a benign clinical course. Only two case reports have described COP in association with ICI therapy and, to date, transformation or overlap with lymphoproliferative disorders such as marginal zone lymphoma has not been documented. We report the case of an 86-year-old male with urothelial carcinoma who developed a progressive, ulcerated, bleeding lesion of the lower lip during adjuvant nivolumab therapy. Histologic examination revealed a dense subepithelial infiltrate of mature plasma cells and lymphocytes. Direct and indirect immunofluorescence studies were negative, excluding autoimmune blistering disorders. Immunohistochemistry showed a predominance of CD138-positive plasma cells with a moderate kappa light-chain shift, CD19 expression, and absence of CD56, Cyclin-D1, and CD117, arguing against a plasma cell neoplasm. Molecular analysis via multiplex PCR revealed a clonal B-cell population with distinct IgH rearrangements, and some EBV-positive cells were also identified by EBER in situ hybridization. The histopathologic and molecular findings suggested a marginal zone lymphoma-like, plasmacytic proliferation arising in the setting of COP. This case illustrates a rare and diagnostically challenging constellation at the intersection of reactive and clonal B-cell proliferations in the context of ICI therapy. Although the lesion demonstrated features of clonality, the overall low B-cell content, indolent clinical course, and lack of systemic involvement support a reactive, immunodeficiency-associated lymphoproliferation rather than overt lymphoma. This case expands the known spectrum of mucocutaneous irAEs and highlights the need for careful clinicopathologic correlation, including immunophenotyping and molecular diagnostics. Awareness of such rare presentations is essential to avoid overdiagnosis and unnecessary systemic treatment in patients with otherwise indolent lesions.

Linear atrophoderma of Moulin (LAM) is a rare, benign dermatosis characterized by unilateral, hyperpigmented, slightly atrophic plaques distributed along Blaschko’s lines. We report the case of an 18-year-old woman with a four-year history of asymptomatic lesions on the right abdomen, thigh, and foot. Histopathology revealed basal layer hyperpigmentation, mild collagen thickening, and a sparse perivascular lymphocytic infiltrate, without sclerosis. The clinical and histological findings confirmed the diagnosis of LAM. Given the stable course and absence of symptoms, a conservative approach with follow-up was adopted. This case underscores the importance of recognizing LAM’s distinctive presentation to avoid unnecessary treatments.