Calvarial tuberculosis in a paediatric patient: a diagnosis not to forget.

We report the case of a 10-year-old boy that presented with a palpable, painless, frontal lesion. Laboratory assessments were unremarkable and the patient was asymptomatic. Initial investigation, with a skull radiograph and unenhanced CT scan, showed a lytic midline frontal lesion involving the inner and outer tables of the skull and a large subgaleal hypodense component. MRI further depicted communication with the epidural space and contact with the superior sagittal sinus (SSS). Subsequent evaluation by Doppler ultrasound and MR angiography excluded a sinus pericranii and showed normal patency of the SSS. Surgical biopsy revealed chronic granulomatous inflammation; PCR was positive for Mycobacterium sp. One year after surgical resection and antitubercular therapy, there are no signs of recurrence. Primary calvarial involvement by tuberculosis is rare, even in developing countries. Familiarity with the expected clinical and imaging features is required to avoid diagnostic delay.

High-Throughput Sequencing Identifies 3 Novel Susceptibility Genes for Hereditary Melanoma.

Cutaneous melanoma is one of the most aggressive human cancers due to its high invasiveness. Germline mutations in high-risk melanoma susceptibility genes have been associated with development hereditary melanoma; however, most genetic culprits remain elusive. To unravel novel susceptibility genes for hereditary melanoma, we performed whole exome sequencing (WES) on eight patients with multiple primary melanomas, high number of nevi, and negative for high and intermediate-risk germline mutations. Thirteen new potentially pathogenic variants were identified after bioinformatics analysis and validation. CDH23, ARHGEF40, and BRD9 were identified as the most promising susceptibility genes in hereditary melanoma. In silico analysis of CDH23 and ARHGEF40 variants provided clues for altered protein structure and function associated with the identified mutations. Then, we also evaluated the clinical value of CDH23, ARHGEF40, and BRD9 expression in sporadic melanoma by using the TCGA dataset (n = 461). No differences were observed in BRD9 expression between melanoma and normal skin samples, nor with melanoma stage, whereas ARHGEF40 was found overexpressed, and CDH23 was downregulated and its loss was associated with worse survival. Altogether, these results reveal three novel genes with clinical relevance in hereditary and sporadic melanoma.

Diffuse neurofibroma--an uncommon cause of alopecia.

Although infrequent, alopecia can be caused by benign cutaneous tumours. Neurofibromas are common benign tumors that originate in the peripheral nerve sheath. Diffuse neurofibroma is a rare variant of neurofibroma that is thought to occur mainly in the head and neck of children and young adults. Histology generally shows an infiltrative tumor, composed of spindle cells in the dermis and subcutaneous tissue. Despite being rare, malignant transformation has been reported. The association between diffuse neurofibromas and neurofibromatosis type 1 still remains to be determined since some authors question the low incidence usually described. We report the case of a 42-year-old man who had a diffuse neurofibroma on the scalp presenting as alopecic plaques.

Diffuse neurofibroma - an uncommon cause of alopecia / Neurofibroma difuso - uma causa rara de alopecia

Although infrequent, alopecia can be caused by benign cutaneous tumours. Neurofibromas are common benign tumors that originate in the peripheral nerve sheath. Diffuse neurofibroma is a rare variant of neurofibroma that is thought to occur mainly in the head and neck of children and young adults. Histology generally shows an infiltrative tumor, composed of spindle cells in the dermis and subcutaneous tissue. Despite being rare, malignant transformation has been reported. The association between diffuse neurofibromas and neurofibromatosis type 1 still remains to be determined since some authors question the low incidence usually described. We report the case of a 42-year-old man who had a diffuse neurofibroma on the scalp presenting as alopecic plaques.

Apesar de infrequente, a alopecia pode ser causada por tumores cutâneos benignos. Os neurofibromas são neoplasias benignas comuns com origem na baínha externa dos nervos. O neurofibroma difuso é uma variante rara de neurofibroma que ocorre tipicamente na cabeça e pescoço de crianças e adultos jovens. Histologicamente caracteriza-se por um tumor infiltrativo, composto por células fusiformes, localizado na derme e tecido celular subcutâneo. Apesar de rara, a transformação maligna já foi descrita. A associação dos neurofibromas difusos e neurofibromatose tipo 1 ainda não está determinada dado que alguns autores contestam a baixa incidência habitualmente referida. Descrevemos o caso de um homem de 42 anos com um neurofibroma difuso do couro cabeludo com aprasentacao de placas de alopecia.

Hyalinizing clear cell carcinoma of salivary glands: a study of extracellular matrix.

Hyalinizing clear cell carcinoma (HCCC) is a recently described low-grade carcinoma of the salivary glands presenting two main histological features: clear neoplastic cells and prominent hyalinized stroma. Our aim was to characterize the composition of the hyalinized stroma in three cases of HCCC. An immuno-histochemical study using laminin and type I, III and IV collagens, fibronectin and tenascin antibodies was performed. In one case, electron microscopy study was also done. Collagen I and fibronectin were always present in tumoral stroma. Collagen III was documented in two cases and tenascin at the invasive front of the neoplasm. Collagen IV and laminin were found around neoplastic cells but not at the interstitial stroma. Foci of basal lamina reduplication and large deposits of long space collagen were observed in EM. This study demonstrates that the hyalinized stroma of HCCC is not formed by the accumulation of basement membrane-type material since it is mostly composed by collagen I and fibronectin.