Fibromatose Agressiva do tipo Desmoide - Revisão Pictórica

• Author(s): Almeida Costa, Nuno ; Santos, João Garrido ; Fonseca, Diogo ; Ribeiro, Maria Filipa ; Malheiro, Maria Leonor
• Date: 2019
• Origin: Acta Radiológica Portuguesa
• Subject(s): Artigos Revisão
• Document Type: Journal article
• Language: Portuguese

Description

Fibromatoses agressivas do tipo desmoide consistem em tumores mesenquimatosos raros que se caraterizam histologicamente por proliferação de fibroblastos e miofibroblastos. Apresentam comportamento intermédio, com tendência a comportamento infiltrativo e recidivante, sem capacidade metastização. Podem localizar-se na parede abdominal, ou em topografia intra ou extra-abdominal. A RM oferece vantagens na avaliação e estadiamento das lesões, evidenciando massas heterogéneas bem ou mal definidas, com sinal intermédio nas sequências ponderadas em T1 e T2, centradas ao plano inter-muscular, com bandas de hipocaptação interna (bandas de colagéneo), e que geralmente exibem halo de gordura (“split fat” sign), e extensão aos planos fasciais (“fascial tail” sign). Lesões com maior intensidade de sinal T2 apresentam maior probabilidade de recorrência. Na ausência de excisão cirúrgica, total ou parcial, a diminuição da intensidade do sinal T2, redução dimensional e a ausência de captação de contraste são características que sustentam eficácia terapêutica.

Aggressive fibromatosis of desmoid type comprises rare mesenchymal tumors characterized histologically by proliferation of fibroblasts and myofibroblasts. These lesions have intermediate behavior,  characterized by infiltrative growth and local recurrence but an inability to metastasize. Deep fibromatosis (desmoid type fibromatosis) can be located in abdominal wall (generally in sutures), intra or extraabdominal. The best imaging modality for evaluation and staging of the deep fibromatoses is MR imaging. These well or ill-defined lesions generally present internal hypointense bands, with lack of enhancement in post contrast images (collagen bundles), are usually centered in an intermuscular location with a rim of fat ("split fat"sign), although invasion of surrounding muscle is frequent. Linear extension along fascial planes (the fascial tail sign) is also a frequent manifestation and is uncommon with other soft-tissue neoplasms. MR image signal intensity may have an implication on tumor recurrence, with a higher recurrence rates in lesions with high T2 signal. In lesions undergoing radiation or drug therapy, MR surveillance has been used to assess response to treatment with a positive response demonstrating decrease in T2 signal, lesion enhancement and lesion size.