Fusion of the genes PHF1 and TFE3 in malignant chondroid syringoma

Background/Aim: Malignant chondroid syringoma is a rare tumor of unknown pathogenesis. Materials and Methods: Genetic analyses were performed on a malignant chondroid syringoma. Results: G-banding analysis of short-term cultured tumor cells yielded the karyotype 46,Y,t(X;6)(p11;p21)[15]/46,XY[2]. RNA sequencing detected an in-frame fusion of PHF1 from 6p21 with TFE3 from Xp11, verified by RT-PCR and Sanger sequencing. Genomic PCR showed that the PHF1-TFE3 junction was identical to the fusion found by RNA sequencing and RT-PCR. Conclusion: Malignant chondroid syringoma is genetically related to tumors with PHF1 rearrangements such as low-grade endometrial sarcoma and ossifying fibromyxoid tumor, but also with tumors having TFE3 rearrangements such as renal cell carcinoma, alveolar soft part sarcoma, PEComa, and epithelioid hemangioendothelioma. Further investigations on malignant chondroid syringomas are needed in order to determine whether genetic heterogeneity exists among them and the clinical impact of the PHF1-TFE3 fusion

Clinical and Histopathological Features of Folliculotropic Mycosis Fungoides: a Norwegian Patient Series

Folliculotropic mycosis fungoides is a variant of cutaneous T-cell lymphoma with distinct clinicopathological features. We describe here the clinical presentation, pathology findings and treatment outcome in 15 Norwegian patients. All patients were diagnosed between 1997 and 2010 at Oslo University Hospital. A spectrum of skin lesions, both typical and atypical, such as leonine facies, acneiform lesions, psoriasiform plaques, purulent ulcerations and cystic milia-like lesions for mycosis fungoides, were seen. Histological examination revealed characteristic infiltration of hair follicles with neoplastic T cells associated with partial destruction of the former. A CD4+ immunophenotype of the neoplastic T cells with loss of one or more T-cell markers was demonstrated. In general, the patients were given more aggressive therapeutic regimens than those with conventional mycosis fungoides, and showed a trend towards more rapid disease progression. In conclusion, this case series confirms the distinct clinical and histological features of folliculotropic mycosis fungoides. Key words: mycosis fungoides; cutaneous T-cell lymphoma; folliculotropic mycosis fungoides

Melanoma staging: Varying precision and terminal digit clustering in Breslow thickness data is evident in a population-based study

Background Errors in Breslow thickness reporting can give misclassification of T category, an important classifier in melanoma staging. Objective We sought to investigate precision (number of digits) and terminal digit clustering in Breslow thickness and potential consequences for T category. Methods All first primary and morphologically verified invasive melanomas in Norway between 2008 and 2015 were included. A smoothing model was fitted to estimate the underlying Breslow thickness distribution without digit clustering. Results Thickness was reported for 13,057 (97.5%) patients; the median was 1.0 mm (range, 0.09-85). It was reported as whole numbers (15.6%), to 1 decimal (78.2%) and 2 decimal places (6.2%)—thin tumors with more precision than thick tumors. Terminal digit clustering was found with marked peaks in the observed frequency distribution for terminal digits 0 and 5, and with drops around these peaks. Terminal digit clustering increased proportions of patients classified with T1 and T4 tumors and decreased proportions classified with T2 and T3. Limitations Breslow thickness was not reported in 2.5% of cases. Conclusions The Norwegian recommendation of measurement to the nearest 0.1 mm was not followed. Terminal digit clustering was marked, with consequences for T category. Pathologists, clinicians, and epidemiologists should know that clustering of thickness data around T category cut points can impact melanoma staging with consequent effect on patient management and prognosis