No abstract

Mélanome métastatique ayant l'aspect d'une tumeur non différenciée de site primaire inconnu: un algorithme immunohistochimique Introduction. L'identification par immunohistochimie du type et du site d'origine dans les tumeurs non différenciées de site primaire inconnu est une exigence fréquente dans la pratique pathologique. Il existe de nombreuses lésions histologiques montrant des aspects morphologiques similaires, avec un diagnostic erroné pouvant entraîner un traitement insuffisant ou excessif. Cela rend la précision du diagnostic extrêmement importante à l'ère des thérapies ciblées. L'objectif de l'étude était d'évaluer le processus de diagnostic dans 50 cas de mélanome présentant des tumeurs peu différenciées ou non différenciées d'origine primaire inconnue, l'accent étant mis sur l'algorithme immunohistochimique.

Introduction. The aim of this study was to investigate several cases of giant cell tumor of bone (TCG), chondroblastoma and aneurysmal bone cyst (ABC) by immunohistochemistry (IHC) with a panel of markers: p63, S-100, CD68, CD56, DOG1, Galectin-1, D2-40, CD34, CD45 and ki-67, some of which proved to be specific for a certain entity. Material and methods. The cases were retrospectively selected from cases processed in our facility where the surgical excision material was histopathologically analyzed in optical microscopy using the usual staining hematoxylin and eosin. The immunohistochemistry exam was performed at INCDVB by indirect method avidin-biotin-peroxidase complex (C-DAB) with polyclonal antibodies (Dako) for S100; CD56, p63, DOG1, CD34, D2-40, CD45, ki67, and Galectin1 were performed in 14 cases out of which 10 were TGC, 3 chondroblastomas, and one primary ABC. Results. Five out of ten TGC investigated showed p63 diff use nuclear expression in the mononuclear cell. None of the 3 cases of chondroblastoma or ABC-primary or secondary (associated with the above mentioned tumors), expressed p63. Other variables, non-specifically encountered in all of the tumors, were emphasized by CD34 (vascular network), ki-67 (index of proliferation), CD45 (inflammatory infi ltrate). DOG1 expression was found positive in all chondroblastoma cases. Conclusions. p63 proved to be a useful biomarker in differentiating giant cell tumor of bone from central giant cell granuloma and other giant cell-rich tumors, especially chondroblastoma and ABC. Chondroblastoma was particularly rewarding in this investigation by demonstrating the dual immunohistochemical phenotype of the neoplastic cells, both chondroblastic (S-100, D2-40) and osteoblastic (CD56 and Galectin -1). DOG1, which is mainly used for the diagnostic of GIST, was found by many to be also specific, in the proper morphopathological context, for chondroblastoma.

Chromophobe renal cell carcinoma (CHRCC) is known for morphologic variability. Besides classic morphology, several other patterns like pigmented adenomatoid, multicystic, even papillary were documented. 10 cases of CHRCC composed of small cell population in various percentages that were analysed using morphologic parameters, immunohistochemistry and next generation sequencing. Patients were 5 males and 5 females with 40-78 age range. Size of tumors ranged from 2.2 cm to 11 cm (mean 5.17 cm). Small cell component comprised 10-80% of total tumor volume, the rest was formed by cells with classic morphology. Immunohistochemical profile followed typical CHRCC immunophenotype with positivity for CD117, CK7 among others. Neuroendocrine markers were negative. Mutations of 13 genes were found: DCIER1, FGFR3, JAK3, SUFO, FAM46C, FANCG, MET, PLCG2, APC, POLE, EPICAM, MUTYH, AR. However, only mutation of PLCG2 is listed as pathogenic. Recognition of small cell variant of CHRCC is not problematic in tumors, where “classic” CHRCC component is present. In limited material, like core biopsy, recognising this pattern could be troublesome.  Very problematic might be in limited material like core biopsy. From our limited data it seems, that small cell morphology has no influence on prognosis.

Evaluation digitale de l'invasion en profondeur des mélanomes, à l'aide de différents marqueurs immunohistochimiques Introduction. Les facteurs histologiques pronostiques les plus importants du mélanome restent la profondeur d'invasion et le taux mitotique. Dans l'ère digitale, la précision (en termes de reproductibilité et de répétabilité inter laboratoires), ainsi que les preuves des images, sont de nouveaux paramètres qualitatifs. L'objectif de l'étude a été d'évaluer, dans une analyse rétrospective, toute différence significative entre les évaluations numériques de Breslow effectuées en utilisant deux colorations immunohistochimiques différentes et l'étalon d'or, la coloration à l'éosine d'hématoxyline. Matériel et méthodes. Nous avons évalué 130 mélanomes cutanés primaires diagnostiqués pour

No abstract

No abstract

No abstract