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Pearls & Oy-sters: Primary Diffuse Leptomeningeal Melanocytosis: A Diagnostic Conundrum
Jeevi Mona Priyadharshni Selvarajan1, Sridhar Epari1, Arpita Sahu1
1From the Departments of Radiation Oncology (J.M.P.S., A.D., A.C., T.G.), Pathology (S.E.), and Radio-diagnosis (A.S.), Tata Memorial Hospital (TMH)/Advanced Centre for Treatment Research & Education in Cancer (ACTREC), Tata Memorial Centre, Homi Bhabha National Institute (HBNI), Mumbai, India.
Abstract:
Primary diffuse leptomeningeal melanocytosis (PDLM) is an extremely rare CNS tumor with nonspecific clinicoradiologic features that overlap considerably with aseptic meningitis posing significant diagnostic and therapeutic challenges. We present one such case report of a patient treated empirically at first presentation as aseptic viral meningitis based on MRI and CSF analysis. Diagnosis of PDLM was established subsequently through meningeal biopsy that demonstrated a melanocytic tumor with fine granular melanin pigment without significant mitoses. Her systemic and ocular examination was unremarkable. Whole-body 18F-fluorodeoxyglucose PET/CT (FDG-PET/CT) did not identify any other primary site. Following ventriculoperitoneal shunt to relieve hydrocephalus, she was treated with definitive craniospinal irradiation plus whole-brain boost and remains stable on periodic clinicoradiologic surveillance. Optimal management of PDLM lacks consensus with role of radiotherapy, chemotherapy, targeted therapy and immunotherapy being controversial.
Insights
Primary diffuse leptomeningeal melanocytosis (PDLM) is a rare CNS tumor often misdiagnosed as meningitis. This case highlights diagnostic challenges and successful craniospinal irradiation treatment for PDLM.
Area of Science:
- Neuro-oncology
- Rare CNS Tumors
Background:
- Primary diffuse leptomeningeal melanocytosis (PDLM) presents with nonspecific symptoms, mimicking aseptic meningitis.
- Diagnostic challenges arise from overlapping clinicoradiologic features with other CNS conditions.
Observation:
- A patient initially treated for aseptic viral meningitis based on MRI and CSF analysis.
- Subsequent meningeal biopsy confirmed PDLM, revealing a melanocytic tumor with melanin pigment.
Findings:
- The patient underwent ventriculoperitoneal shunting for hydrocephalus.
- Definitive treatment included craniospinal irradiation with a whole-brain boost, resulting in stability.
Implications:
- This case underscores the importance of considering PDLM in differential diagnoses.
- Optimal management strategies for PDLM remain controversial, necessitating further research into radiotherapy, chemotherapy, and novel therapies.
