A 74‐Year‐Old Man with a Jugular Foramen Mass

Clinical History and Imaging

Seventy‐four‐year old man with a history of gait instability, bilateral hand numbness and hearing loss. An MRI showed a 4.4 × 2.5 × 3.4 centimeters (CC by AP by transverse) avidly enhancing heterogeneous T1 hypointense and T2 hyperintense mass with cystic components centered in the left cerebellopontine angle and widening extending through the left jugular foramen into the left carotid space. There was moderate to marked mass effect in the left middle cerebellar peduncle and the brainstem (Figure 1A,B). The patient was treated with radiation therapy and a course of dexamethasone. He returned 2 months after completing treatment with complaints of nausea, dizziness, gait imbalance and blurry vision. A repeat MRI was done showing fourth ventricle enlargement. The patient was admitted for VP shunt placement. This required multiple revisions. The patient was discharged to a rehabilitation facility. Shortly after discharge, the patient was found to be pale, diaphoretic and in respiratory distress. He progressed to asystole and expired.

Figure 1.

 

Pathological Findings

At autopsy a firm, pink mass was visualized. The tumor was seen with passage through the jugular foramen and intracranial extension with compression of left cerebellum and brainstem (Figure 1C–E). Tissue sections stained with hematoxylin and eosin show spindled cells with dense chromatin (Figure 1F). No mitotic figures were identified. Immunohistochemical staining of the tumor demonstrates diffuse S100 (Figure 1G) and collagen IV staining (Figure 1H) with a Ki‐67 labeling index of 1%–2%. What is your diagnosis?

Diagnosis

Schwannoma of the jugular foramen.

Discussion

Schwannoma in the jugular foramen may arise from CN IX through XII. The specific nerve of origin is difficult, if not impossible, to identify in many cases. Clinically they are often confused with glomus jugulare tumor (jugulotympanic paraganglioma) because of their growth pattern, anatomic location and symptoms 1. On MRI, glomus jugulare tumors characteristically show intense contrast enhancement and multiple small voids (“salt and pepper” appearance), whereas schwannomas typically do not show internal flow voids, with the exception of highly vascular vestibular schwannomas which can show them peripherally. Intracranial nerve sheath tumors represent only 4%–8% of intracranial neoplasms. Most intracranial schwannomas are associated with neurofibromatosis type 2. Jugular foramen schwannomas represent 3%–4% of these tumors. Grossly the tumors tend to be dumbbell‐shaped or round and are well‐circumscribed. The cell of origin is the Schwann cell. Grossly, some tumors may display a cystic component with moderate vascularity. The cellular component classically contains architectural regions designated as Antoni type A and Antoni type B. Antoni A regions are densely packed with spindled cells. Antoni B areas are sparsely populated with loosely organized stellate cells. Verocay bodies, palisades of spindled nuclei alternating with anuclear processes, may also be present.

The symptoms of jugular foramen schwannomas include problems with speaking and swallowing and are related to vessel and nerve compression. These slow‐growing tumors often fill a significant amount of space prior to causing symptoms. Once a tumor has reached a critical size, which varies by precise location, signs and symptoms of nerve root compression and brain stem compression can evolve quickly to the syndrome of upper brain stem compression. Patients may present with headache, vomiting and neck stiffness, with global impairment of all mental functions, progressing from lethargy to drowsiness and confusion and then to a semi‐comatose state. In medullary compression, death can occur in minutes with sudden respiratory arrest and acute hypotension. Treatment for jugular foramen schwannoma has included radiosurgery 2 and excision 3, 4.