Invasive Crooke cell adenoma in a patient with diffuse large B-cell lymphoma

Crooke cell adenoma (CCA) is an aggressive corticotroph subtype of pituitary adenoma often with cyclically elevated blood adrenocorticotropic hormone (ACTH), which preoperative diagnosis is challenging especially in the context of a functionally silent invasive tumor and a history of high-stage malignancy such as diffuse large B-cell lymphoma (DLBCL). Here, we report the first case of invasive CCA in a patient with DLBCL. A 71 year-old previously healthy man was recently diagnosed with DLBCL that was treated with CHOP-R chemotherapy. Within one week of completing his first cycle of chemotherapy, he had a frontal headache that progressed to right-sided proptosis. Cranial MRI showed a heterogeneously enhancing mass with invasion into the sellar and suprasellar compartment, compression of the optic chiasm, as well as extension into the clivus, bilateral cavernous sinuses, and the prepontine cistern. He underwent a partial resection for the pituitary tumor debulking. Pathological examination revealed CCA with invasion into the adjacent tissue. The patient had no history of Cushing disease or syndrome, but his blood ACTH was found to be elevated on the operation day. Our present case and literature review suggest that comorbidity of CCA or ACTH-producing adenoma and B-cell lymphoma deserves awareness in our clinical practice, as these two diseases and/or their therapies may interact substantially. CAA should be considered in the major differential diagnosis for an invasive sellar tumor, even without blood ACTH elevation and/or with a history of malignant lymphoma.