PMC10392811_01
MRI Brain Initial, 3 Month Surveillance Scan, Post-Surgery and Post-Treatment MRI. (A) Coronal enhanced T1-weighted MRI shows diffuse enlargement and diminished enhancement of the pituitary gland. (B) Follow up MRI 3 months later shows further enlargement of the pituitary (arrowhead) with suprasellar extension compressing the optic chiasm. (C) Residual tumor surrounding the surgical cavity (asterisk) following transsphenoidal resection. (D) MRI 10 weeks later upon completion of therapy showing complete resolution.
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MRI of the brain demonstrated a 19x11 x 11 mm intrasellar mass without compression of the optic chiasm, Figure 1A. Repeat MRI brain demonstrated interval enlargement of the sellar mass with compression of the central and left optic chiasm and adjacent left optic tract with focal extension into the bilateral cavernous sinuses, Figure 1B. She underwent partial transsphenoidal tumor resection (Figure 1C) and pathologic examination revealed malignant lymphoma replacing the pituitary gland, Figure 2A. She was in complete remission (CR) after 2 cycles (Figure 1D) and has remained in CR for the past 8 years.
Excisional Biopsy, Pituitary Tumor and FISH Testing. The excisional biopsy of the pituitary lesion revealed a diffuse proliferation of large lymphocytes with open chromatin and prominent nuclei; mitoses are frequent (A, H&E x 40). IHC studies showed the lymphocytes are positive for CD20, BCL2, MYC with a high proliferative rate by Ki-67 (B-E, x 20). The lymphocytes are negative for CD10 and EBER ISH. FISH study revealed BCL6 gene rearrangement (F, green and red arrows indicate separation of break-apart gene probes) and multiple copies of MYC, BCL2, IGL, and IGK.
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She underwent partial transsphenoidal tumor resection (Figure 1C) and pathologic examination revealed malignant lymphoma replacing the pituitary gland, Figure 2A. Immunohistochemistry showed the neoplastic lymphocytes were diffusely positive for CD20, CD79a, PAX5, MUM1, MYC (60%), and BCL2 (90%) and weakly positive for BCL6, Figure 2B-D. The proliferation rate by Ki-67 was high (>90%), Figure 2E. Extra copies of IGH, IGK, BCL2, IGL loci, and of chromosome 8 were also detected on FISH, Figure 2F.