CASE REPORT J Neurosurg 126:1725–1730, 2017 D iffuse large B-cell lymphoma (DLBCL) is the most common form of lymphoid malignancy and most frequent type of non-Hodgkin lymphoma (NHL) in the world across age and demographics; 15,43 it accounts for approximately 30% of all lymphomas. DLBCL is most commonly found in middle-aged or elderly individuals, with a median age at diagnosis in the sixth decade of life. Men are at slightly higher risk than women. 18 Patients commonly present with a painless mass in the neck, groin, or abdomen associated with an array of constitutional symptoms, including fever, weight loss, night sweats, and fatigue. Central nervous system involvement may be ob- served in 2%–5% of cases; however, DLBCL presenting as a primary CNS lesion is quite rare, representing less than 1% of all primary brain tumors. 14 Primary CNS pre- sentation is usually associated with immunosuppression but has recently been identifed with increasing frequency in immunocompetent individuals. 14 Although the WHO classifes DLBCL as a single dis- ease entity, there is signifcant variation in clinical presen- tation, behavior, response to treatment, and long-term out- comes. 36 DLBCL is typically treated with a combination of anthracycline chemotherapy and immunomodulatory medications, 7,13,29,30,37 with nearly 60%–70% of patients achieving a cure. 36 In this paper we describe a unique case of a 61-year-old woman diagnosed with a pituitary DLBCL, an activated B-cell immunophenotype, and growth hormone hyperpla- sia. Because this is the only reported case of its kind, we review the entity in the context of the pertinent literature and describe its management. Case Report History and Presentation A 61-year-old, previously healthy woman presented with worsening headaches. She had laboratory evidence of elevated prolactin of 63 ng/ml (reference 2.8–26.0 ng/ml) and hypothyroidism (thyroid-stimulating hormone [TSH] 0.03 mU/L [reference 0.35–4.94 mU/L] and free thyrox- ine 0.45 ng/dl [reference 0.71–1.85 ng/dl]). Additionally, she had an elevation in insulin-like growth factor-1 (IGF- ABBREVIATIONS ACTH = adrenocorticotropic hormone; DLBCL = diffuse large B-cell lymphoma; GHRH = growth hormone–releasing hormone; IGF-1 = insulin-like growth factor-1; NHL = non-Hodgkin lymphoma; PCNSL = primary central nervous system lymphoma; R-CHOP = rituximab, cyclophosphamide, doxorubicin hydrochloride, vincris- tine sulfate, and prednisone; SIADH = syndrome of inappropriate antidiuretic hormone; TSH = thyroid-stimulating hormone. SUBMITTED April 4, 2016. ACCEPTED May 26, 2016. INCLUDE WHEN CITING Published online August 12, 2016; DOI: 10.3171/2016.5.JNS16828. Primary pituitary diffuse large B-cell lymphoma with somatotroph hyperplasia and acromegaly: case report Vijay M. Ravindra, MD, MSPH, 1 Amol Raheja, MBBS, 1 Heather Corn, MD, 2 Meghan Driscoll, MD, 3 Corrine Welt, MD, 2 Debra L. Simmons, MD, MS, 2 and William T. Couldwell, MD, PhD 1 1 Department of Neurosurgery, Clinical Neurosciences Center and Huntsman Cancer Institute, 2 Department of Internal Medicine, Division of Endocrinology, and 3 Department of Pathology, University of Utah, Salt Lake City, Utah Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma and comprises approxi- mately 30% of all lymphomas. Patients typically present with a nonpainful mass in the neck, groin, or abdomen associ- ated with constitutional symptoms. In this report, however, the authors describe a rare case of a 61-year-old woman with hyperprolactinemia, hypothyroidism, and acromegaly (elevation of insulin-like growth factor-1 [IGF-1]) with elevated growth hormone–releasing hormone (GHRH) in whom an MRI demonstrated diffuse enlargement of the pituitary gland. Despite medical treatment, the patient had persistent elevation of IGF-1. She underwent a transsphenoidal biopsy, which yielded a diagnosis of DLBCL with an activated B-cell immunophenotype with somatotroph hyperplasia. After stereo- tactic radiation therapy in combination with chemotherapy, she is currently in remission from her lymphoma and has normalized IGF-1 levels without medical therapy, 8 months after her histopathological diagnosis. This is the only reported case of its kind and displays the importance of a broad differential diagnosis, multidisciplinary evaluation, and critical intraoperative decision-making when treating atypical sellar lesions. https://thejns.org/doi/abs/10.3171/2016.5.JNS16828 KEY WORDS pituitary surgery; lymphoma; B-cell; somatotroph hyperplasia ©AANS, 2017 J Neurosurg Volume 126 • May 2017 1725