Primary Pituitary Lymphoma in Immunocompetent Patients: A Report on Two Case Studies and the Review of Literature

Abstract

Primary pituitary lymphoma (PPL) represents an extremely rare entity. Here, we have reported two recently identified cases of immunocompetent PPL having diffuse large B-cell lymphoma by surgical biopsy. Both patients had hypopituitarism, with one patient developing right ptosis. In both patients, MRI and FDG-PET/CT depicted sellar mass that extended into the cavernous sinus with the right sphenoid also present in one of the patients. No systemic disease was found in these two patients. Surprisingly, we found that both patients had infiltrative lesions in sphenoid sinus mucosa pathologically, but the sphenoid bones that composed the sellar base were visually intact during the biopsy procedure. Chemotherapy was administered to both patients, where one patient achieved remission at the recent follow-up, whereas the other one did not respond to the treatment. The diagnosis of PPL is usually difficult if solely dependent on history, clinical presentation, biochemical indexes, and radiographic findings. We have also updated and reviewed the epidemiologic features, clinical presentations, pathological characteristics, potential mechanisms, therapeutic orientation, and prognostic advances of PPL. A total of 40 cases (including ours and four pediatric patients), histologically diagnosed, were analyzed in terms of clinical presentation, endocrine abnormality, radiological features, pathology, treatment, and follow-up. Hypopituitarism and headache were the most common presentation of PPL, while diabetes insipidus was reported in 13 patients (43.3%). B cell lymphoma was the most common type of pathology, followed by T-cell and NK/T cell. PPL was more invasive in nature at the suprasellar region (72.5%), cavernous sinus (52.5%), and sphenoidal sinus (27.5%) in 29, 21, and 11 patients, respectively. Pediatric patients with PPL seem to be different compared to their adult counterparts in terms of pathogenesis, clinical presentation, and radiological features. The management of PPL usually follows the treatment protocols for PCNSL but has a poor prognosis compared to the pituitary involvement of systemic lymphoma.

Pituitary Gland as a Rare Primary Localization of Lymphoma

“…PPL cannot be precisely identified in the preoperative period and can only be diagnosed with histopathological examination. Although the majority of PPL cases are of B lymphocyte origin (80%), natural killer and T cell lymphoma may also be present in some areas (7). A study observed that in some cases, it is also possible to encounter signs of inflammation or adenomatous tissue, which has also been mentioned above (10) (20,21).…”

“…Although Tarabay et al in 2016 observed a slight female predominance in the distribution of cases (female:male ratio 1.35:1), this difference was not seen in the recent studies (female:male ratio 1:1 and 1.12:1, respectively). Moreover, it can appear in all age groups, with a peak incidence observed between the 5 th and the 6 th decade of life (5)(6)(7). Pituitary lymphoma can be either primary or secondary.…”

Primary pituitary lymphoma successfully treated with Bruton’s tyrosine kinase inhibitor monotherapy: case report

“…Primary central nervous system lymphoma is generally treated with chemotherapy based on high-dose MTX, which bypasses the blood-brain barrier, but since the pituitary gland does not have a blood-brain barrier it allows for the wider variety of efficient options including: high-dose MTX 13 ; cyclophosphamide, doxorubicin hydrochloride, vincristine sulfate, and prednisone (CHOP) therapy 14 ; but also, other protocols with varying efficacy 3,15,16 . Because of impaired renal function and the patients advanced age, neither high-dose MTXbased nor CHOP therapy 7 were considered an option in our case, and oral tirabrutinib was chosen instead.…”

“…Malignant lymphomas originating from the central nervous system, or primary central nervous system lymphoma (PCNSL) account for about 3% of intracranial malignancies 1 , with those arising within the sella turcica region being extremely rare 2 . Primary malignant lymphoma of the pituitary gland (primary pituitary lymphoma, PPL) is generally considered when a lymphoma is confined to the sella or parasellar region, without systemic invasion 3 . The relevant clinical symptoms of include headache, hypopituitarism, and visual field and acuity disturbances.…”

Coexistence of Pituitary Adenoma and Primary Pituitary Lymphoma: A Case Report and Review of the Literature

“…The local immune changes in the pituitary gland may be brought about by tumorigenesis. It is reported that primary pituitary lymphoma can develop in immunosuppressed individuals ( 11 ). At the same time, the occurrence and development of pituitary adenomas are closely related to immune infiltration ( 12 ).…”