Q. A patient presents with hearing loss and balance problems. Histopathology of the lesion shows Antony A and Antony B areas and Verocay bodies. What is the most likely diagnosis?

Explanation

## Correct Answer: D. Schwannoma ✅ Schwannoma (acoustic neuroma) is a benign nerve sheath tumor arising from Schwann cells, classically presenting with unilateral hearing loss and balance disturbance due to compression of the vestibulocochlear nerve (CN VIII). The histopathological hallmark is the presence of **Antony A and Antony B areas** with **Verocay bodies**. Antony A areas show tightly packed spindle cells with minimal stroma, while Antony B areas are looser, myxoid regions. Verocay bodies are pathognomonic—they are palisaded arrangements of nuclei around a central acellular zone composed of neural filaments. These features are diagnostic of schwannoma and distinguish it from other CNS tumors. The clinical presentation of CN VIII involvement (hearing loss + vertigo/balance problems) combined with these specific histological findings makes schwannoma the definitive diagnosis. Schwannomas are typically solitary in sporadic cases but multiple bilateral schwannomas suggest neurofibromatosis type 2 (NF2), which is an important Indian clinical consideration given the prevalence of hereditary cancer syndromes. ## Why the other options are wrong **A. Meningioma** — Meningiomas arise from arachnoid cap cells and show whorled patterns, psammoma bodies, and hemangiopericytoma-like areas—NOT Antony A/B areas or Verocay bodies. While meningiomas can present with CN VIII compression, their histology is distinctly different. This is a trap for students who remember 'CN VIII compression' without verifying the histopathology. **B. Medulloblastoma** — Medulloblastoma is a highly malignant pediatric tumor of the posterior fossa showing small round blue cells, high mitotic activity, and rosette formations (Homer Wright or Flexner-Wintersteiner rosettes)—never Antony A/B or Verocay bodies. It presents with hydrocephalus and ataxia, not isolated CN VIII dysfunction. The benign, well-differentiated histology described rules this out entirely. **C. Ependymoma** — Ependymomas arise from ependymal cells lining the ventricular system and show perivascular rosettes and true ependymal rosettes with a central lumen—not Antony A/B areas or Verocay bodies. They typically present with hydrocephalus rather than isolated CN VIII compression. The specific histological findings described are incompatible with ependymoma. ## High-Yield Facts - **Verocay bodies** (palisaded nuclei with central acellular zone) are pathognomonic for schwannoma and distinguish it from neurofibroma. - **Antony A areas** = densely packed spindle cells; **Antony B areas** = loose, myxoid stroma—both present in schwannoma, absent in other nerve sheath tumors. - **CN VIII schwannoma** (acoustic neuroma) presents with unilateral sensorineural hearing loss + vertigo/balance dysfunction—the classic triad. - **Bilateral CN VIII schwannomas** are diagnostic of **neurofibromatosis type 2 (NF2)**—an important screening consideration in Indian populations with family history. - Schwannomas are **benign, slow-growing** tumors; malignant transformation is extremely rare (<1%), unlike neurofibromas which can undergo sarcomatous change. - **S-100 protein** is positive in schwannomas (and neurofibromas); **EMA** is negative in schwannomas but positive in neurofibromas—key immunohistochemical distinction. ## Mnemonics **VEROCAY = Schwannoma** **V**erocay bodies, **E**ncapsulated, **R**ound nuclei palisaded, **O**rdered spindle cells, **C**lear S-100+, **A**ntony A/B areas, **Y**ellow (lipid-rich). Use when you see 'palisaded nuclei' or 'nerve sheath tumor' in a question. **Antony A vs B (Memory Hook)** **A** = **A**cute/dense (tightly packed), **B** = **B**ackground/loose (myxoid). Both present = Schwannoma. Use when histology describes both dense and loose areas. ## NBE Trap NBE pairs CN VIII compression (which can occur with meningioma or other tumors) with the specific histological findings to trap students who rely only on clinical presentation. The discriminator is the pathognomonic Antony A/B + Verocay bodies, which are unique to schwannoma. ## Clinical Pearl In Indian clinical practice, a patient presenting with progressive unilateral hearing loss and vertigo should raise suspicion for acoustic neuroma; MRI with contrast (gadolinium) shows a characteristic "dumbbell-shaped" tumor at the cerebellopontine angle. Always ask about family history of NF2, as bilateral schwannomas in a young Indian patient warrant genetic counseling and screening of first-degree relatives. _Reference: Robbins Ch. 28 (Nervous System Tumors); Harrison Ch. 375 (Neuro-oncology)_