Journal of Cutaneous Pathology最新文献

CIC::DUX4 fusion sarcoma represents a rare and aggressive subtype of undifferentiated small round blue cell tumors. We report on a 23-year-old African male who developed a rapidly enlarging inferolateral left buttock nodule with ulceration. After debulking excision of the lesion, histologic sections demonstrated sheets and lobules of atypical round blue cells with significant cytologic atypia. Prominent foci of atypical mitotic figures and tissue necrosis were present. Tumoral cells stained strongly and diffusely using MDM2, vimentin, WT1 and CD99 immunohistochemical (IHC) markers. Molecular testing was performed and highlighted CIC::DUX4 gene fusion positivity, making the diagnosis of a CIC::DUX4 sarcoma (CDS). Post-surgical excision, the patient showed no disease on imaging and underwent five cycles of adjuvant chemotherapy with no recurrence observed at the eight-month follow-up. With fewer than 200 cases reported in the literature and somewhat nonspecific clinicopathologic characteristics, CIC::DUX4 sarcoma presents a diagnostic challenge. This case underlines the importance of molecular diagnostics in undifferentiated sarcomas and presents a rare primary cutaneous manifestation of CIC::DUX4 fusion sarcoma. Additionally, we provide a review of the literature to aid in recognition, diagnosis, and treatment of this rare entity.

In 1973, Dr. Martin C. Mihm, Jr. presented the finding that congenital melanocytic nevi, when viewed at low magnification, resemble superficial and deep perivascular dermatitis, forming the so-called "pseudoinflammatory" pattern. One year earlier, Dr. Richard A. Sagebiel had put forward the concept of "pseudovascular spaces" in melanocytic nevi. A retrospective look at these early studies confirms that alert observation at the microscope can lead to a deeper understanding of the fundamental biology underlying melanocytic tumors.

Dr. Martin C. Mihm, Jr.'s innovative work on the dysplastic nevus achieved a milestone in his chapter in the World Health Organisation Classification of Skin Tumours (WHO-C). WHO-C presents a dichotomous classification (high-grade versus low-grade dysplastic nevi) and a quantitative metric to assess melanocytic nuclear enlargement. The Duke classification is a related approach that provides mostly quantitative histopathologic criteria for dysplastic nevi and gives due weight to architectural features as well as cytology. This paper proposes and illustrates updated criteria for scoring and grading melanocytic dysplasia, incorporating some of the definitions and categories of WHO-C, while refining the quantitative and architectural elements of the Duke grading system to facilitate more detailed and precise assessment of dysplastic nevi.

Background: Xeroderma pigmentosum (XP) is a genodermatosis, characterized both by premature aging and significantly increased risk of non-melanoma and melanoma skin cancers at an early age. However, limited literature is available on the common histopathological subtypes of basal cell carcinoma (BCC) in these patients.

Methods: In this ambispective case series, we recruited patients of XP who had either a currently present skin tumor or previously excised one, provided their histopathological sections were available. Cytogenetic analysis was performed in all the patients. The histopathological findings were recorded by two trained dermatopathologists.

Results: Of 22 recruited patients with XP, 12 patients had 41 BCCs, and 23 (56.09%) of them showed a high-risk histopathological subtype. Basosquamous carcinoma (10, 24.39%) was the most frequent high-risk tumor followed by infiltrative variant (7, 17.07%). Mixed-histopathological subtypes were noted in six (14.63%) cases, and all of them had a high-risk component. The low-risk subtypes included nodular (n = 17, 41.46%) and superficial BCC (1, 2.43%). Though a deep dermal involvement was seen in 27 (65.85%) lesions, none showed a perineural invasion or necrosis. Three (7.31%) lesions showed ulceration, while 10 (24.39%) showed presence of pigmentation.

Conclusions: A frequent occurrence of high-risk basal cell carcinoma was noted in patients with XP-mandating creation of appropriate treatment and follow-up strategies in these patients.

Background: Melanocytic tumors with perineuriomatous differentiation may pose diagnostic challenges. This study explores characteristics of perineuriomatous melanocytic nevi, an entity merging features of perineurioma and melanocytic nevi. The aim is to elucidate histopathological features of perineuriomatous nevi to allow dermatopathologists to recognize them and differentiate them from other spindle cell lesions.

Method: This study reviews four cases (2020-2023) of melanocytic nevi with perineuriomatous components.

Results: All cases comprised adults (median age: 64.50, mean age: 60.25), with a female predominance, and exhibited clinical features characterized by irregular brown macules or papules on the trunk and extremities. Histopathologically, all lesions were compound, and biphasic patterns were evident, encompassing superficial nevoid and deeper spindled populations arranged in whorled fascicles and embedded in a sclerotic or myxoid stroma. Immunohistochemistry revealed expression of at least one perineuriomatous marker in deeper cells. Cases were assessed and compared with previously published cases for comprehensive insights. Three of our four cases demonstrated the presence of a junctional component that was smaller than the dermal component. We suggest that this unusual feature, which we term the "reverse shoulder", may allow dermatopathologists to help consider perineurial differentiation in the appropriate setting.

Conclusion: Perineuriomatous nevi can pose diagnostic challenges. This study contributes to the growing body of literature on perineuriomatous nevi, emphasizing their unique features and the importance of accurate diagnosis to avoid unnecessary interventions.

Background: There is growing evidence that the Spitz group of melanocytic neoplasms should be restricted to those harboring kinase receptor fusions and HRAS mutations/11p15 amplification. The presence of genomic alterations characteristic of conventional melanomas (BRAF and NRAS mutations) precludes a diagnosis of a Spitz neoplasm. It is often challenging to distinguish Spitz neoplasms from conventional melanomas with spitzoid morphology on histopathological grounds alone.

Methods: We report a series of 70 consecutive melanocytic tumors in which targeted sequencing was indicated to distinguish Spitz from spitzoid neoplasms and to classify Spitz neoplasms along the biological spectrum.

Results: Final diagnoses incorporating molecular results included 12 conventional melanomas (nine of which with NRAS mutations), five Spitz melanomas, 35 atypical Spitz tumors, eight Spitz nevi, three melanocytic tumors with a MAP2K1 mutation, and seven desmoplastic Spitz nevi/tumors. There were significant discrepancies between initial diagnoses and final diagnoses after incorporating molecular results in 24 (34%) cases, including nine conventional melanomas favored to be Spitz neoplasms and nine Spitz neoplasms favored to be conventional melanomas.

Conclusions: It is often not possible to reliably distinguish Spitz neoplasms from spitzoid melanocytic tumors without identifying their driver genomic alterations. Applying next-generation sequencing in diagnostically problematic tumors improves diagnostic accuracy.

Background: Folliculotropic mycosis fungoides (FMF) is a rare cutaneous malignancy that can be mistaken for inflammatory diseases, such as discoid lupus erythematosus (DLE), due to the variability of histopathological findings.

Methods: This study aims to provide dermatopathologists with evidence-based histopathologic criteria to distinguish DLE from FMF by reporting overlapping and distinguishing microscopic features. Forty-three biopsies from patients with a confirmed diagnosis of DLE or FMF were graded for the presence or absence of 18 histopathologic features.

Results: The main histopathologic findings present in nearly all DLE and FMF biopsies were folliculocentric and folliculotropic patterns. Comedones, granulomas, and folliculitis were not prominent. Follicular hyperplasia, follicular plugging, interstitial mucin, lichenoid/interface dermatitis, and plasma cells were significantly more common in DLE biopsies, while follicular mucinosis and eosinophils were significantly more common in FMF samples. Cytologic atypia ranged from none to mild in DLE and mild to moderate in FMF. Rarely, both sets of biopsies contained epidermotropism, spongiosis, or peri-eccrine infiltration.

Conclusion: While many histopathological features present in DLE overlap with features found in FMF, such as folliculocentrism and folliculotropism, significant differences do exist. Therefore, when diagnosing FMF, it is important to follow established criteria that differentiate this malignancy from inflammatory conditions such as DLE.

Cutaneous neurocristic hamartoma (CNH) is a rare lesion composed of neural crest derivatives, thought to arise from aberrant migration and differentiation of neural crest cells. Recognition of CNH may be difficult, as they may resemble giant congenital nevus, and development of proliferative nodules (PNs) may raise concern for malignant transformation. Assessment of gene expression in CNH and PNs derived from CNH may offer insight into pathogenesis and suggest clinically useful biomarkers to identify these entities. This study investigates gene expression patterns in a congenital CNH and three separate PNs derived from that CNH with giant congenital nevus and malignant melanoma as comparator groups. Comparison of PN to CNH demonstrates downregulation of WIF1, which encodes as a tumor suppressor, and loss of WIF1 expression might explain the progression from CNH to PN. Comparison of gene expression in PN and CNH with giant congenital nevus and malignant melanoma shows relative overexpression of IGF2 and H19 in CNH and PN, suggesting that abnormal imprinting and IGF2 overexpression may have integral functions in the foundation of CNH.

Kaposi sarcoma is a human herpesvirus 8-associated angio-proliferative tumor arising from lymphatic endothelial cells. Four clinical subtypes are known: classic, epidemic, endemic, and iatrogenic. The development of Kaposi sarcoma and lymphedema may be interlinked, where each condition could potentially support the progression of the other. Post-mastectomy lymphedema is a commonly recognized complication following radical mastectomy. Angiosarcoma is the most frequently reported neoplasm in such a situation. We present a 72-year-old female who developed Kaposi sarcoma on the same side of mastectomy 9 years following her initial diagnosis and treatment for cancer breast. The diagnosis of Kaposi sarcoma was based on the histopathologic findings and was confirmed with immunohistochemical staining for human herpes virus 8 and D2-40. Lymphedema may be associated with local immune suppression manifested in the form of defective cell-mediated immunity and antigen-presenting cell migration defect which may facilitate development of neoplasms. It is important to differentiate Kaposi sarcoma from other vascular tumors which may have a much worse prognosis. Patients with lymphedema should receive appropriate management and undergo long-term follow-up for early detection of any potential malignancies.