A novel MPLKIP-variant in three Finnish patients with non-photosensitive trichothiodystrophy type 4

Trichothiodystrophy is a group of multisystem neuroectodermal disorders with dysplastic hair as the cardinal symptom. We describe three patients from two Finnish families in whom whole-exome sequencing revealed a novel homozygous variant, c.26del, p.(Pro9Glnfs*144) in the MPLKIP-gene, confirming the diagnosis of non-photosensitive trichothiodystrophy type 4 (TTD4). The variant was confirmed by Sanger sequencing and inherited from unaffected carrier parents. This report adds to the literature by expanding the genetic and phenotypic spectra of MPLKIP-related trichothiodystrophy. We describe dysmorphic features in the patients and provide a comparison of clinical characteristics in patients with TTD4 reported to date.Peer reviewe

LRIG1 is a positive prognostic marker in Merkel cell carcinoma and Merkel cell carcinoma expresses epithelial stem cell markers

Merkel cell carcinoma (MCC) is a rare and aggressive neuroendocrine malignancy of the skin. The cell of origin of MCC is thus far unknown and proposed cells of origin include Merkel cells, pro-/pre- or pre-B cells, epithelial stem cells, and dermal stem cells. In this study, we aimed to shed further light on the possibility that a subset of MCC tumors arise from epithelial stem cells of the skin by examining the expression of hair follicle and epidermal stem cell markers in MCC and normal human skin. We also aimed to elucidate any correlation between the expression of these markers and tumor Merkel cell polyomavirus (MCPyV) status or other clinicopathological characteristics or patient survival. Expression of CK19, SOX9, LGR5, and LRIG1 in MCC and normal human skin was studied by immunohistochemistry, and the staining patterns or intensities were statistically correlated with patient, tumor, MCPyV, and survival parameters. In a cohort of 137 cases of MCC, we observed dot-like immunoexpression of CK19 in 30 cases (22.1%) and homogeneous expression in 103 cases (75.7%). We also observed positive immunoexpression of SOX9 in 21 cases (15.3%), LGR5 in 118 cases (86.1%), and LRIG1 in 117 cases (86.0%). Immunoexpression of LRIG1 was found to correlate with better overall and MCC-specific survival. We observed frequent immunoexpression of several hair follicle and epidermal stem cell markers in MCC and found LRIG1 to be a positive prognostic marker in MCC.Peer reviewe

Eccrine Porocarcinoma: Clinical and Histopathological Study of 14 Patients with Special Emphasis on Sentinel Lymph Node Biopsy

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