Rare Primary ALK-Positive Anaplastic Large Cell Lymphoma of the Central Nervous System.

Anaplastic large cell lymphoma (ALCL) is a rapidly growing and aggressive hematological malignancy. We present the case of a 12-year-old adolescent boy with a 2-week history of left iliac fossa and presacral pain radiating to the lower limbs associated with emesis and constipation. Subsequently, the patient developed poorly controlled hypertension and progressive lower limb weakness. Imaging revealed an intradural extramedullary mass at the L1 level, and pathology reported large, atypical cells consistent with ALK -positive ALCL. This case highlights the rarity of isolated intradural extramedullary manifestations in the pediatric population. Keywords : Anaplastic large-cell lymphoma; human central nervous system neoplasms; pediatric oncology; intradural neoplasms; treatment outcome; ALK protein, human.