Recurrent MPNST in Mosaic Localized Neurofibromatosis: A Rare Scenario – Review

Introduction: Mosaic localized neurofibromatosis is a rare subtype of Neurofibromatosis type 1 (NF1) which is largely underdiagnosed till recently. The occurrence of Malignant Peripheral Nerve Sheath Tumor (MPNST) in such a setting is extremely rare with only 5 cases reported in literature till date. Method: Narrative review based on published case reports, obtained by searching on PubMed and Google scholar. Results/ Discussion: The pattern of recurrence and prognosis are different from conventional MPNST. The cases are of variable histologic grade, but showed improved survival outcome with surgical treatment alone. Even though local recurrence is common, none of these cases showed distant metastasis. This is in contrast with conventional MPNST which shows poor survival and frequent metastasis even with multimodality treatment. Specific treatment guidelines are yet to be established because of its rarity. Conclusions: Even though histomorphology remains the mainstay of diagnosis of MPNST, further cytogenetic and molecular analysis of these cases are crucial in the invention of new targeted drugs. In this review, we discuss the clinical outcome of this rare entity and highlight the importance of understanding the molecular events for future targeted