[1637] Choroid Plexus Carcinoma in Adults: Clinicopathologic, Immunohistochemical, and Imaging Studies of Cases Presenting at Unusual Sites.

Steven C Smith, James E Madory, Cynthia Welsh, Michael T Smith, Mila Blaivas. University of Michigan Health System, Ann Arbor; Medical University of South Carolina, Charleston

Background: Although choroid plexus carcinoma is considered more common in pediatric populations, <20 cases have been reported in adults, including, rarely, within the extraventricular brain parenchyma.
Design: Consult files of the University of Michigan and Medical University of South Carolina were reviewed.
Results: Three cases were identified; gender/ages F/67, M/44, and M/60. Presenting symptoms included headache, hearing loss, and memory loss with dysnomia, respectively. Imaging identified sites as left lateral temporal; right cerebellopontine angle, as right anterior temporal. Imaging interpretation of the first was primary glioma versus metastatic carcinoma; the second, acoustic schwannoma versus meningioma, and third, again, glioma versus metastasis. Two of the three cases (F/67 and M/44) showed a clear transition from normal choroid plexus to atypical, malignant cells including solid areas with increased nuclear hyperchromasia and mitoses consistent with frank carcinoma. The third case showed a highly anaplastic morphology with sheets of pleiomorphic cells, apoptosis and necrosis reminiscent of glioblastoma. However, multiple foci demonstrated differentiation into papillae with thin-walled vessels surrounded by hobnailed cells, suggesting choroid plexus histogenesis. In the F/67 and M/60 cases, GFAP and S100 stained negative or only focally, both were positive in the third M/44. Prealbumin/transthyretin was positive, supporting choroid plexus origin in the two more poorly differentiated cases (M/60 and F/67), including in the more anaplastic component. In the M/60 and M/44 cases, synaptophysin was positive, and MIB-1 proliferative index 90% and 13%, respectively. In the M/60 and M/44 cases, both CK7 and CK20 were weak to negative, while in the F/67 and M/44 cases CEA staining was negative and positive, respectively.
Conclusions: Choroid plexus carcinoma presents rarely in adulthood and may occur at sites mimicking more common malignancies. Two of three cases showed a transition from identified choroid plexus tissue, the third evinced a markedly dedifferentiated morphology with only focal papillation. in such cases we still observed clear positivity with prealbumin/transthyretin, supporting the utility of this marker in identification of tissue of origin.
Category: Neuropathology

Tuesday, March 1, 2011 1:00 PM

Poster Session IV # 235, Tuesday Afternoon


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