[Fat-forming solitary fibrous tumor with NAB2/ STAT6 gene fusion. Case report of genial location and literature review]. / Tumor fibroso solitario variedad lipomatosa con fusión génica NAB2/STAT6. Estudio de un caso de localización geniana y revisión de la literatura.

The lipomatous variety solitary fibrous tumor is a soft tissue neoplasm composed of mature adipose tissue and hemangiopericytoma areas. A 53-year-old man consulted for facial asymmetry and maxillofacial magnetic resonance imaging showed a cystic lesion, 3 x 2 cm in size, in front of the anterior wall of the maxillary sinus. Histologically, there were dense spindle cells expressing CD34, CD99, Bcl-2, and STAT6, myxoid zones, hemangiopericytomatous blood vessels, and S100 positive adipocytes. NAB2/STAT6 gene fusion was revealed by RT-PCR. The main differential diagnosis was raised with the spindle cell lipoma and malignant variant of the lipomatous solitary fibrous tumor. STAT6 overexpression and NAB2/STAT6 gene fusion are specific for lipomatous solitary fibrous tumor and the presence of lipoblasts and atypical lipomatous tumor areas suggests malignancy. These tumors located in the head and neck region have a benign biological behavior.

Tumor fibroso solitario variedad lipomatosa con fusión génica NAB2/STAT6. Estudio de un caso de localización geniana y revisión de la literatura / Fat-forming solitary fibrous tumor with NAB2/ STAT6 gene fusion. Case report of genial location and literature review

El tumor fibroso solitario variedad lipomatosa es una neoplasia de partes blandas compuesta por tejido adiposo maduro y áreas de hemangiopericitoma. Un varón de 53 años se presentó clínicamente con asimetría facial. La resonancia magnética maxilofacial demostró una lesión quística, de 3 x 2 cm, por delante de la pared anterior del seno maxilar. Histológicamente, había áreas fusocelulares densas que expresaban CD34, CD99, Bcl-2 y STAT6, zonas mixoides, vasos sanguíneos hemangiopericitomatosos y adipocitos S100 positivos. La fusión génica NAB2/STAT6 fue revelada mediante RT-PCR. El principal diagnóstico diferencial se planteó con el lipoma de células fusiformes y la variante maligna del tumor fibroso solitario lipomatoso. La sobreexpresión de STAT6 y la fusión génica NAB2-STAT6 son específicas del tumor fibroso solitario lipomatoso y la presencia de lipoblastos y áreas de tumor lipomatoso atípico sugiere malignidad. Estos tumores en cabeza y cuello tienen un comportamiento biológico benigno.(AU)

The lipomatous variety solitary fibrous tumor is a soft tissue neoplasm composed of mature adipose tissue and hemangiopericytoma areas. A 53-year-old man consulted for facial asymmetry and maxillofacial magnetic resonance imaging showed a cystic lesion, 3 x 2 cm in size, in front of the anterior wall of the maxillary sinus. Histologically, there were dense spindle cells expressing CD34, CD99, Bcl-2, and STAT6, myxoid zones, hemangiopericytomatous blood vessels, and S100 positive adipocytes. NAB2/STAT6 gene fusion was revealed by RT-PCR. The main differential diagnosis was raised with the spindle cell lipoma and malignant variant of the lipomatous solitary fibrous tumor. STAT6 overexpression and NAB2/STAT6 gene fusion are specific for lipomatous solitary fibrous tumor and the presence of lipoblasts and atypical lipomatous tumor areas suggests malignancy. These tumors located in the head and neck region have a benign biological behavior.(AU)

Balanitis Xerotica Obliterans Associated With Differentiated Penile Intraepithelial Neoplasia and "Bramble-Bush" Elastic Fibers Accumulation: A Finding Not Specific for Penicillamine Intake.

We describe the association of balanitis xerotica obliterans and differentiated penile intraepithelial neoplasia (PeIN) with dermal elastosis and "bramble-bush" elastic fibers in a diabetic patient with no history of penicillamine intake. An 84-year-old man presented with urethral obstruction syndrome that required postectomy, meatotomy, and foreskin excision. Histopathological examination revealed changes of lichen sclerosus and differentiated PeIN. Orcein staining showed striking dermal elastosis and transepidermal elimination of elastic fibers. At higher magnification, multiple serrations and buds arising from the borders of the elastic fibers were observed giving the so-called bramble-bush appearance. Balanitis xerotica obliterans is considered a premalignant disease, and 14% of patients have evidence of PeIN. The differentiated subtype can be difficult to diagnose because of the minimal basal cell atypia, so a striking dermal elastosis, which may even occur before the neoplasm becomes invasive, may facilitate its diagnosis. The term "acquired perforating dermatosis" seems appropriate to describe those cases of perforating elastosis that occurs in adults with systemic diseases. The bramble-bush appearance of elastic fibers is not specific for penicillamine-induced elastopathy, and it may occur in other diseases, such as diabetes mellitus. This peculiar morphology of elastic fibers may be related to the enzymatic imbalance between matrix metalloproteinases and lysyl oxidase, an enzyme required for the cross-linking of elastic fibers.