Tenosynovial giant cell tumor.

Tenosynovial Giant Cell Tumor (TGCT) is a group of typically benign lesions arising from the synovium of joints, bursae and tendon sheaths. Depending on their growth pattern and clinical course, they are divided into localized and diffuse types. It is predominantly caused by a mutation in the stromal cells of the synovial membrane leading to overexpression of the colony stimulating factor 1 that recruits CSF1R-expressing cells of the mononuclear phagocyte lineage into the tumor mass. The lesions contain mainly histiocyte-like and synovial cells accompanied by varying numbers of multinucleated giant cells, mononuclear cells, foam cells, inflammatory cells and hemosiderin deposits. The gold standard for detect- ing and monitoring the disease is MRI, where the characteristic hemosiderin accumulation can be best appreciated, but it is a histological examination that is most conclusive. The main treatment is surgical resection of all pathological tissue, but radio- and chemotherapy are also viable options for certain groups of patients.

Updating superficial siderosis of the central nervous system: bleeding of a dorsal osteophyte into the subarachnoid space from a perforating artery.

Superficial siderosis of the central nervous system (SSCNS) is an uncommon and often unrecognized disorder that results from recurrent and persistent bleeding into the subarachnoid space. Currently, there is no effective treatment for SSCNS. The identification and surgical resolution of the cause of bleeding remains the most reliable method of treatment, but the cause of bleeding is often not apparent. The identified sources of recurrent bleeding have typically included neoplasms, vascular malformations, brachial plexus or nerve root injury or avulsion, and previous head and spinal surgery. An association between recurrent bleeding in the CNS and dural abnormalities in the spine has recently been suggested. Dural tears have been identified in relation to a protruding disc or osteophyte. Also in these patients, the exact mechanism of bleeding remains unknown because of a lack of objective surgical data, even in patients who undergo neurosurgical procedures.The present case concerns a 48-year-old man who presented with longstanding symptoms of mild hearing loss and mild gait ataxia. A diagnosis of SSCNS was made in light of the patient's history and the findings on physical examination, imaging, and laboratory testing. MRI and CT detected a small calcific osteophyte in the anterior epidural space of T8-9. The patient underwent surgical removal of the bone spur and dural tear repair. During the surgery, the authors detected a perforating artery, which was on the osteophyte, that was bleeding into the subarachnoid space. This case shows a possible mechanism of chronic bleeding from an osteophyte into the subarachnoid space. In the literature currently available, a perforating artery on an osteophyte bleeding into the subarachnoid space has never been described in SSCNS.

Dermatofibroma. Análisis clínicopatológico de 10 años en el servicio de dermatopatología del Hospital General de México / Dermatofibroma. A ten year clinico-pathological analysis in the department of dermatopathology at the hospital general de méxico

El dermatofibroma es un tumor fibrohistiocítico común en la práctica de la dermatología, ocurre de predominio en mujeres jóvenes, con topografía preferencial en las extremidades inferiores; es de lento crecimiento y representa una mezcla de células fibroblásticas e histiocíticas con disposición característica. Siendo el Hospital General de México un pilar en el diagnóstico y tratamiento de pacientes con afecciones cutáneas, se realizó un estudio observacional, retrospectivo, longitudinal, descriptivo y abierto, incluyendo 187 especímenes de dermatofibromas para determinar sus características clinico-patológicas, en el periodo de enero de 1991 a diciembre de 2000. La frecuencia general fue de 1.23 por ciento en relación con los padecimientos cutáneos evaluados en el periodo. El predominio fue para el grupo de edad de 21-30 años, con un predominio mujer:hombre de 4:1. La topografía predominante fueron las extremidades inferiores, siendo las superiores el segundo lugar. En el análisis histopatológico, los dermatofibromas clásicos fueron 62.24 por ciento, atípicos el 18.7 por ciento, histiocitofibromas 14.43 por ciento e histiocitomas 1.6 por ciento. Dentro de los cambios epidérmicos destacó la acantosis simple, seguido por atrofia epidérmica; los cambios dérmicos revelaron presencia constante de patrón estoriforme, células epitelioides, nodos colagenosos, edema del estroma, hemosiderina, neovascularización periférica, xantomatización e incluso en pequeña proporción mitosis. Se encontró un caso de dermatofibroma atípico con metaplasia ósea y 2 con lesiones con aspecto intratumoral de colagenoma esclerótico. Se clasificaron 2 dermatofibromas como variante liquenoide y 3 como erosivos o ulcerados. Se concluye que hacen falta rutas diagnósticas específicas para el estudio de los dermatofibromas y neoplasias fibrohistiocíticas relacionadas, y que las variantes morfológicas distan mucho de modificar su evolución clínico-patológica (AU)