Title: A 62-year-old male with intractable seizures

Authors: Maryam Abdo MD, Nelli S. Lakis MD

Institution: The University of Kansas Health system

Clinical History: A 62-year-old male presented to the emergency department with intractable seizures.

Radiology: 

Magnetic resonance imaging (MRI) of brain showed densely calcified mass centered in the right centrum, semiovale along the deep precentral sulcus measuring 2.2 x 2.0 cm. The lesion demonstrated heterogeneous internal T2 hyperintensity and linear peripheral and heterogeneous internal enhancement.

Representative Histology / IHC: 

Specimen was entirely submitted and examined. Histology from the resection showed predominantly a fibroosseous lesion associated with granular amorphous to chondromyxoid fibrillary cores with abundant calcification and ossification. The bone appeared non-neoplastic and surrounding some of the fragments are bland-appearing spindle to epithelioid cells with variable fibrous stroma. There was also some surrounding brain parenchyma (mostly detached & fragments), which is mildly hypercellular and gliotic.

Immunohistochemical stains and special stains were performed; GFAP and IDH1-R132H highlighted the brain fragments while negative in the spindle cells. EMA, STAT6, Olig2, S100, SV40, GMS, B-amyloid, AFB were negative. CD68 highlighted scattered macrophages. Ki67 was low < 1%.

Comprehensive next-gene sequencing showed no molecular abnormalities.

GFAP immunostain highlights the brain fragments while negative in the spindle cells.

Questions for Viewers:

1)     What is the final diagnosis?

2)     What are the important differential diagnoses?

3)     What is the standard of treatment for this lesion?