Atypical plasma cell neoplasm
A Chromogenic in situ hybridization (CISH) preparation for determination of kappa and lambda expression was performed which showed strong universal lambda expression (blue stain) and no kappa expression (red stain). (Figure 5) These results indicate a lambda-restricted monoclonal population of plasma cells.
The most common pathologies involving jugular foramen include paragangliomas, schwannomas and meningiomas, all of which were initially considered for this patient. The most common presentations of a jugular foramen tumor are symptoms of ipsilateral lower cranial nerve dysfunction such as hearing loss, tinnitus and dysphagia. Other relatively rare pathologies that can arise from jugular foramen include chondrosarcoma, chordoma, cholesteatoma and inflammatory granuloma. (8) Intracranial involvement in plasmacytomas and multiple myeloma is rare and most of the time it results from extension of a tumor in cranial vault, skull base or para-nasal sinuses. The incidence of intracranial plasmacytoma with multiple myelomas has been estimated to be less than 3%. The most common locations reported thus far are frontal bone, orbital tip, clivus, sphenoid sinus and parietal regions. From imaging perspectives, they mostly appear iso- to hyper- intense on a T1 weighted MRI and they usually intensely enhance after gadolinium injection. (2, 3, 4, 9) Myeloma specific blood work up for our patient was performed shortly after the biopsy and it revealed following results: serum kappa free light chain: 0.84mg/dl (normal range: 0.33-1.94mg/dl), lambda free light chain: 274 mg/dl (normal range: 0.57-2.63), kappa to lambda ratio: <0.01 (normal range: 0.26-1.65) and M-spike: 3.42g/dl (normal range: 0.00-0.01gm/dl). The skeletal survey showed multiple lytic lesions mostly in long bones of right upper extremity. However, bone view of head CT surprisingly was not significant for any classic lytic lesions except some bony erosion around left jugular foramen. Given his recent renal failure, laboratory and imaging findings plus the pathology from his intracranial lesion, the patient was diagnosed with multiple myeloma; however he didn't receive any treatment because he expired a few days later due to end stage renal failure. Immunohistochemistry and flow cytometry help differentiate plasmacytomas from other tumors such as lymphomas. Plasmacytomas usually express CD138, and being positive for cytoplasmic light chains, either lambda or kappa, proves the monoclonal nature of plasmacytic proliferation. (1) Only a handful of jugular foramen plasmacytomas are reported in the literature, (5, 6, 7) however it should be considered in differential diagnosis of tumors in this region, particularly when a clinical or laboratory evidence of multiple myeloma exists.
Contributed by Ali Mahta, MD, Zhongde Du, MD, Ewa Borys, MD, Bob Carter, MD-PhD, Scott R. Vandenberg, MD, PhD, Santosh Kesari, MD, PhD