TY - JOUR A1 - Kneitz, Hermann A1 - Rose, Christian A1 - Glutsch, Valerie A1 - Goebeler, Matthias T1 - Recurrence of a cellular blue nevus with satellitosis ā€” a diagnostic pitfall with clinical consequences JF - Dermatopathology N2 - Blue nevus is a benign melanocytic lesion, typically asymptomatic and of unknown etiology. Several histologic and clinical variants have been distinguished, the most frequent being common blue nevus, cellular blue nevus, and combined blue nevus. Although melanocytic nevi with a satellite lesion are usually suggestive of locally advanced malignant melanoma, very few cases of blue nevi with satellite lesions have been reported. The diagnosis of common or cellular blue nevi is generally straightforward; however, the presence of structures such as irregular edges or satellitosis are highly suggestive for malignancy, and differential diagnoses such as locally advanced malignant melanoma and malignant blue nevus should be considered. Recurrent blue nevi can display atypical features not seen in the primary lesion, such as pleomorphism and mitotic activity. They usually tend to follow a benign course; however, in some cases, recurrence may indicate malignant transformation. We here report the unique case of a 64-year-old woman with a recurrent cellular blue nevus accompanied by satellite lesions. Such a biological behavior resulting in a clinical presentation as a melanoma-like lesion is a rarity in blue nevus and has not been described before. KW - common blue nevus KW - cell rich blue nevus KW - satellitosis KW - immunohistochemistry KW - skin Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-297436 SN - 2296-3529 VL - 9 IS - 4 SP - 361 EP - 367 ER - TY - JOUR A1 - Glutsch, Valerie A1 - Wobser, Marion A1 - Schilling, Bastian A1 - Gesierich, Anja A1 - Goebeler, Matthias A1 - Kneitz, Hermann T1 - PRAME expression as helpful immunohistochemical marker in rhabdoid melanoma JF - Dermatopathology N2 - Background: Rhabdoid melanoma is a rare variant of malignant melanoma with characteristic cytomorphologic features. Due to the potential loss of conventional melanocytic markers, histopathologic diagnosis is often challenging. We hypothesize that immunostaining for PReferentially expressed Antigen in MElanoma (PRAME) might have the potential to uncover the melanocytic origin of these dedifferentiated tumors. Methods: Four cases of rhabdoid primary melanomas were assessed by immunohistochemistry for expression of PRAME and conventional melanocytic markers. Immunohistochemical expression patterns were analyzed in the rhabdoid primaries and, if available, associated metastases. Results: All four cases of rhabdoid primary melanomas showed a strong nuclear positivity for PRAME, while the expression of conventional melanocytic markers S100, MART-1, SOX-10 and HMB-45 was variable between the analyzed cases. Conclusions: In summary, we report four cases of rhabdoid primary melanoma with high to intermediate expression of PRAME despite the partial and variable loss of other melanocytic markers. Hence, PRAME might facilitate the recognition of this highly aggressive entity to avoid misdiagnosis due to histopathologic pitfalls. KW - PRAME KW - rhabdoid differentiation KW - rhabdoid melanoma KW - immunohistochemistry KW - melanocytic markers Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-284115 SN - 2296-3529 VL - 9 IS - 2 SP - 148 EP - 157 ER - TY - JOUR A1 - Frings, Verena Gerlinde A1 - Goebeler, Matthias A1 - Schilling, Bastian A1 - Kneitz, Hermann T1 - Aberrant cytoplasmic connexin43 expression as a helpful marker in vascular neoplasms JF - Journal of Cutaneous Pathology N2 - Background Gap junctions consisting of connexins (Cx) are fundamental in controlling cell proliferation, differentiation, and cell death. Cx43 is the most broadly expressed Cx in humans and is attributed an important role in skin tumor development. Its role in cutaneous vascular neoplasms is yet unknown. Methods Fifteen cases each of cutaneous angiosarcoma (cAS), Kaposi sarcoma (KS), and cherry hemangioma (CH) were assessed by immunohistochemistry for expression of Cx43. Expression pattern, intensity, and percentage of positively stained cells were analyzed. Solid basal cell carcinomas served as positive and healthy skin as negative controls. Results Most cases of cAS presented with a strong Cx43 staining of almost all tumor cells, whereas endothelia of KS showed medium expression and CH showed mostly weak expression. In comparison with KS or cAS, the staining intensity of CH was significantly lower (Pā€‰ā‰¤ā€‰0.001). All tissue sections of both cAS and KS were characterized by a mostly diffuse, cytoplasmic staining pattern of the vascular endothelia. None of those showed nuclear staining. Conclusion The high-to-intermediate expression of Cx43 observed in all cases of cAS and KS suggests that this Cx may play a role in the development of malignant vascular neoplasms and serve as a helpful diagnostic marker. KW - Kaposi sarcoma KW - cutaneous angiosarcoma KW - Cx43 KW - hemangioma KW - immunohistochemistry Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-258412 VL - 48 IS - 11 ER -