ABSTRACT
Background Imaging with F18-fluorodeoxyglucose PET/CT is used to determine sites of abnormal glucose metabolism and can be used to characterize and localize many types of tumors. Aim To assess the prevalence of multiple primary malignant neoplasms (MPMN) detected by PET/CT in cancer patients. Material and Methods F18-fluorodeoxyglucose PET/CT scans performed to 800 patients with a newly diagnosed cancer or with already treated tumors were retrospectively reviewed. In patients whose examination described incidental findings not related to the primary tumor, a research was done about further laboratory, imaging or pathological studies. Results In 188 PET/CT scans (23%) an incidental finding was found. Of these, 66 (35%) were considered as MPMN, 12 as atypical metastases of a known primary tumor, 14 as false positive images (inflammatory or physiologic uptake) and 29 as benign or low grade tumors. In 67 cases (36% of all incidental tumors), the finding was not confirmed. Seven percent of patients with a newly diagnosed tumor had a synchronic MPMN detected by PET/CT. Nine percent of patients with treated tumors developed a metachronous MPMN during their follow up. The most common incidental tumors were thyroid cancer in 15 cases, kidney cancer in 13, lung cancer in 10, colorectal carcinoma in 9, breast cancer in 6, prostate cancer in 4, non-Hodgkin lymphoma in 3 and pancreatic cancer in 2. Conclusions A MPMN is detected by PET/CT in a significant number of cancer patients.
Subject(s)
Humans , Adolescent , Adult , Middle Aged , Aged , Aged, 80 and over , Young Adult , Carcinoma/diagnostic imaging , Positron Emission Tomography Computed Tomography , Neoplasms, Multiple Primary/diagnostic imaging , Carcinoma/classification , Carcinoma/complications , Adenocarcinoma/classification , Adenocarcinoma/complications , Adenocarcinoma/diagnostic imaging , Cross-Sectional Studies , Radiopharmaceuticals , Fluorodeoxyglucose F18 , Early Detection of Cancer/methods , Neoplasms, Multiple Primary/classification , Neoplasms, Multiple Primary/complicationsABSTRACT
Os gliomas múltiplos são relativamente raros e podem ser classificados didaticamente de acordo com: a) a época da apresentação, em precoces (quando presentes desde o diagnóstico inicial) ou tardios (quando presentes durante a evolução); e b) as características dos exames de imagem, em multifocais (quando há evidência de contiguidade das lesões) ou multicêntricos (quando não é possível identificar contiguidade das lesões). Entre os 212 pacientes com diagnóstico anatomopatológico de glioma, acompanhados prospectivamente no setor de neuro-oncologia de março/90 a setembro/99, 15 (7 por cento) apresentaram lesões múltiplas. Descrevemos 4 casos característicos de cada uma das possíveis apresentações: multicêntrico precoce, multicêntrico tardio, multifocal precoce e multifocal tardio, com ênfase nas características de imagem e possíveis diagnósticos diferenciais. O diagnóstico diferencial das lesões múltiplas no sistema nervoso central inclui doenças inflamatórias e infecciosas, além de metástases. A possibilidade de tratar-se de tumores de origem glial, entretanto, deve ser sempre lembrada, mesmo naqueles pacientes com diagnóstico de neoplasia sistêmica conhecida, conforme já descrito na literatura. O diagnóstico histológico se impõe, uma vez que as características de imagem não permitem diagnóstico de certeza.