Follicular dendritic sarcoma within a focus of Castleman's disease. Serial FDG PET/CT in the follow up of recurrence with histopathologic confirmation.

We report the case of a 30 year-old man with previous history of melanoma and new diagnoses of localized abdominal Castleman's disease with a focus of follicular dendritic sarcoma within the Castleman's tumor. He presented soon after with a single enlarged abdominal lymph node characterized and followed-up by FDG PET/CT as a low grade malignancy consistent with Castleman's recurrence. However, other imaging techniques raised the possibility of sarcoma/ melanoma recurrence. Final surgical resection allowed histological confirmation of the FDG PET/CT findings. To our knowledge, this is one of the few cases in the literature of Castleman's disease and follicular dendritic sarcoma association in the same focus. This is the first paper to our knowledge to use FDG PET/CT as the follow-up imaging tool for serial characterization of recurrence of Castleman's disease and follicular dendritic sarcoma. FDG PET/CT may be useful in the differentiation between Castleman's disease and malignancies associated with this disease.

Follicular dendritic sarcoma within a focus of Castleman's disease. Serial FDG PET/CT in the follow up of recurrence with histopathologic confirmation

Presentamos el caso de un varón de 30 años con historia previa de melanoma y nuevo diagnóstico de enfermedad de Castleman localizada en el abdomen, con un foco de sarcoma dendrítico folicular dentro del tumor de Castleman. Poco después presentó una adenopatía caracterizada y seguida con PET/TAC con FDG con criterio de bajo grado de malignidad concordante con una recurrencia de Castleman. Sin embargo, otras técnicas de imagen sugerían la posibilidad de recurrencia de sarcoma/melanoma. Una resección quirúrgica final permitió la confirmación histológica de los hallazgos de la PET/TAC con FDG. Hasta lo que sabemos, este es uno de los pocos casos en la literatura en el que aparece una asociación de enfermedad de Castleman y sarcoma dendrítico folicular en el mismo foco. Este es el primer trabajo, que sepamos, en el que se utiliza PET/TAC con FDG como herramienta de imagen para el seguimiento y caracterización seriada de la recurrencia de la enfermedad de Castleman y sarcoma dendrítico folicular. La PET/TAC con FDG puede ser útil en la diferenciación entre la enfermedad de Castleman y tumores malignos asociados con esta enfermedad

We report the case of a 30 year-old man with previous history of melanoma and new diagnoses of localized abdominal Castleman's disease with a focus of follicular dendritic sarcoma within the Castleman's tumor. He presented soon after with a single enlarged abdominal lymph node characterized and followed-up by FDG PET/CT as a low grade malignancy consistent with Castleman's recurrence. However, other imaging techniques raised the possibility of sarcoma/ melanoma recurrence. Final surgical resection allowed histological confirmation of the FDG PET/CT findings. To our knowledge, this is one of the few cases in the literature of Castleman's disease and follicular dendritic sarcoma association in the same focus. This is the first paper to our knowledge to use FDG PET/CT as the follow-up imaging tool for serial characterization of recurrence of Castleman's disease and follicular dendritic sarcoma. FDG PET/CT may be useful in the differentiation between Castleman's disease and malignancies associated with this disease