Which of the following is seen in Schwannoma?
Correct Answer: Antoni A and Antoni B pattern
Description: Ans. c. Antoni A and Antoni B pattern (Ref: Robbins 9/e p257. 854, 8/e p1340)Antoni A and Antoni B pattern is seen in schwannoma.'Schwannoma: In the Antoni AQ pattern of growth, elongated cells with cytoplasmic processes are arranged in fascicles in areas of moderate to high cellularity and scant stromal matrix; the 'nuclear-free zones' of processes that lie between the regions of nuclear palisading are termed Verocay bodiesQ. In the Antoni pattern of growth, the tumor is less densely cellular and consists of a loose meshwork of cells, microcysts and myxoid stroma.' - Robbins 9/e p854.Area marked with arrow represents the pattern of growth, in which the tumor is less densely cellular and consists of a loose mesh work of cells, microcysts and myxoid stroma, Antoni B pattern of growth."Schwannoma: In the Antoni AQ pattern of growth, elongated cells with cytoplasmic processes are arranged in fascicles in areas of moderate to high cellularity and scant stromal matrix; the "nuclear-free zones" of processes that lie between the regions of nuclear palisading are termed Verocay bodiesQ. In the Antoni BQ pattern of growth, the tumor is less densely cellular and consists of a loose meshwork of cells, microcysts and myxoid stroma. "-- Robbins 9/e p854Fig. 15: Tumor showing cellular areas (Antoni A). including Verocay bodies (far right). As well as looser, myxoid regions (Antoni B. center)SchwannomaBenign tumorArise from the neural crest-derived Schwann cellQCause symptoms by local compression of involved nerve or adjacent structures (brainstem or spinal cord).Schwannomas are a component of NF2QLoss of expression of the NF2 gene product. merlinQ, is a consistent finding in all schwannomas.MorphologyWell-circumscribed, encapsulated masses that are attached to the nerve but can be separated from itOn microscopic examination tumors show a mixture of two growth patternsIn the Antoni AQ pattern of growth, elongated cells with cytoplasmic processes are arranged in fascicles in areas of moderate to high cellularity & scant stromal matrix: the "nuclear-free zones" of processes that lie between the regions of nuclear palisading are termed Verocay bodiesQ.In the Antoni BQ pattern of growth, tumor is less densely cellular & consists of a loose meshwork of cells, microcysts & my xoid stroma.Schwann cell origin of these tumors is borne out by their S-100 immunoreactivityQ.Malignant change is extremely rareQ, but local recurrence can follow incomplete resection.Clinical Features:Within the cranial vault most schwannomas occur at cerebellopontine angle, where they are attached to the vestibular branch of eighth nerveQAffected individuals often present with tinnitus & hearing loss; tumor is often referred to as an "acoustic neuroma," although it actually is a vestibular Schwannoma.Elsewhere within dura, sensory nerves are preferentially involved, including branches of the trigeminal nerve & dorsal rootsQ.When extradural, schwannomas are most commonly found in association with large nerve trunksQ, where motor & sensory modalities are intermixed.
Category:
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