Extra Gastrointestinal Stromal Tumor treated with imatinib in a patient with Neurofibromatosis type 1

Gastrointestinal Stromal Tumor in a Patient with Neurofibromatosis Type 1 That Was Successfully Treated with Regorafenib

An unconscious 55-year-old man with a history of neurofibromatosis type 1 (NF1) was transported to the emergency department and was diagnosed with acute renal failure owing to a large bladder tumor. A submucosal tumor was also identified in the duodenum. The patient was diagnosed with a primary gastrointestinal stromal tumor (GIST) of the bladder and duodenum. After six cycles of regorafenib therapy, 18F-fluorodeoxyglucose accumulation in the duodenal GIST on positron emission tomography-computed tomography (PET-CT) showed a partial metabolic response. Currently, no standard drug therapy for unresectable or relapsed NF1-associated GIST has been established. Regorafenib may thus be considered as and appropriate initial therapy.

The value of 18F-FDG PET/CT in patient with neurofibromatosis type 1: A case report and literature review

RATIONALE

Neurofibromatosis type one (NF1) is characterized by cutaneous and nervous lesions, and the tendency to form plexiform neurofibromas (PNFs). PNFs may undergo malignant transformation into a malignant peripheral nerve sheath tumors (MPNSTs). MPNSTs often carry an significant morbidity and mortality.

PATIENT CONCERNS

A 17-year-old man with gradually increased multiple subcutaneous soft lesions. He also presented with numerous lentigines and multiple café-au-lait macules on his body.

DIAGNOSES

These were collagen neurofibroma, which were definitively diagnosed by pathology. NF1 was eventually diagnosed.

INTERVENTIONS

These lesions were abnormal uptake of radiotracer, when he underwent positron emission tomography (PET) with fluorine-18-fluorodeoxyglucose (FDG) scanning. Standard uptake value (SUV) and other parameters can help to distinguish benign and malignant lesions in patient with NF1. He was underwent serials F-FDG PET/CT examinations to followed up, in order to monitor these lesions malignant transformation.

OUTCOMES

So far, these subcutaneous soft lesions were not malignant transformation.

LESSONS

F-FDG PET/CT is being increasingly used as an imaging modality to discover the systemic lesions and to discriminate between benign and malignant plexiform neurofibromas.