Hypophysitis: An update on the novel forms, diagnosis and management of disorders of pituitary inflammation

Hypophysitis is a heterogeneous condition that leads to inflammation of the sella and/or suprasellar region, potentially resulting in hormonal deficiencies and/or mass effects. A preponderance of hypophysitis subtypes have an underlying autoimmune aetiology. The overall incidence and prevalence of hypophysitis has dramatically increased over the past decade, mainly due to increased awareness of the condition in the medical community, improvements in imaging techniques, and a rise in the occurrence of certain forms of hypophysitis such as IgG4 hypophysitis (IgG4Hy) and immune checkpoint inhibitor induced hypophysitis (ICIHy). The clinical presentation varies from an asymptomatic condition to a fatal disease often as a result of electrolyte abnormalities due to glucocorticoid deficiency in the context of adrenal crisis from central adrenal insufficiency. Milder forms of hypophysitis are treated with replacement of deficient hormones while more acute presentations with mass effects require glucocorticoid therapy, immunosuppressive therapy or surgery. Timely diagnosis and interventions are keys to prevention of the lethal complications of this disease. In this review, we provide an update on the recent advances in the field of pituitary autoimmunity, with an emphasis on autoimmune hypophysitis and novel forms of hypophysitis such as anti-PIT1 hypophysitis, IgG4Hy and ICIHy.

Hypophysitis

In this article, an overview is presented of hypophysitis in terms of current clinical and experimental findings, with discussion of the anatomic and histopathologic classification of primary hypophysitis and factors associated with secondary hypophysitis. In addition, discusses the pathophysiology, clinical features, management, and prognosis associated with this disease are discussed.

Variant of lymphocytic infundibulo-neurohypophysitis presenting with unique clinical and radiological features

Lymphocytic hypophysitis (LYH) is a chronic inflammation that primarily affects the pituitary gland. This disorder has recently been classified into lymphocytic adenohypophysitis (LAH), lymphocytic infundibulo-neurohypophysitis (LINH), and lymphocytic infundibulo-panhypophysitis (LIPH) according to the affected area. We report a case of LINH in a 68-year-old woman who presented with diabetes insipidus (DI). In this case, the posterior lobe was affected in both endocrinological assessment and magnetic resonance imaging (MRI) findings. In contrast, the anterior pituitary was not affected in endocrinological assessment but was affected in MRI findings. Indeed, the patient did not develop hypopituitarism. We believed that these clinical and radiological features were unique in regard to the classification of LYH. To confirm the classification of LYH and the distinction from pituitary adenoma, a pituitary biopsy was performed. Based on the pathological and endocrinological assessment, the patient's disorder was finally diagnosed as a variant of LINH. Current evidence recommends that surgical intervention for LYH should be avoided because the natural course of LYH is essentially self-limiting. Therefore, the accumulation of the knowledge of many variants of LYH is important for the preoperative differential diagnosis of pituitary masses. Our clinical observation could be useful for avoiding unnecessary surgical intervention.

Anatomic and pathologic spectrum of pituitary infundibulum lesions

OBJECTIVE

The pathologic spectrum of pituitary infundibulum disease is diverse. We reviewed 65 infundibular lesions in 44 adult and 21 pediatric patients and summarized their imaging features and clinical presentation.

CONCLUSION

The spectrum of pathology involving the pituitary infundibulum is broad yet distinct from other pathology in the sella and parasellar region. Pituitary stalk lesions can be grouped into three categories: congenital and developmental, inflammatory and infectious, and neoplastic. Knowledge of the imaging appearance of diseases specific to adults and to children is important for accurate diagnosis and treatment.

[Hypophysitis]

Hypophysitis is a rare endocrine disorder with a female predilection affecting mainly young women during late pregnancy and in the postpartum period. The clinical, histopathological and morphological findings and the association of the disease with other autoimmune disorders allow most cases of hypophysitis to be included among the autoimmune diseases. This potentially life-threatening condition should be suspected especially in women of reproductive age who present with hypopituitarism or evidence of pituitary mass-induced headaches and visual symptoms. The natural history of hypophysitis is variable. At the present time, the treatment is only symptomatic but there is no absolute agreement among endocrinologists about the optimal management of this condition. In this review, aetiology, symptoms, clinical classification, diagnosis and treatment of hypophysitis are discussed with a special emphasis on the most recent literature.

Spectrum of different types of hypophysitis: a clinicopathologic study of hypophysitis in 31 cases

Hypophysitis has been histologically classified into five types: lymphocytic hypophysitis (LYH), granulomatous hypophysitis (GRH), xanthogranulomatous hypophysitis (XGH), xanthomatous hypophysitis (XH), and necrotizing hypophysitis. The present study evaluated 31 cases of hypophysitis to clarify their characteristic clinicopathologic features. The lesions were histologically classified into four groups: LYH (22 cases) including lymphocytic adenohypophysitis (LAH) (19 cases) and lymphocytic infundibuloneurohypophysitis (LINH) (3 cases), GRH (5 cases), XGH (2 cases), and XH (2 cases). In each group, the pituitary gland showed lymphocytic infiltration associated with focal or diffuse hypophysial destruction of variable severity and fibrosis. Histologic and clinical overlap among different types of hypophysitis, especially between LAH and LINH, suggest that these entities may have similar etiologic background and/or represent different stages of the same lesion. Considering the sampling sites and clinical manifestations, LAH may not usually involve the neurohypophysis, but LINH may often extend to the adenohypophysitis. A selective loss of adrenocorticotropic hormone-positive cells was seen in two patients with LAH despite only very slight lymphoplasmacytic infiltration. This suggests that there may be at least two causative mechanisms for hypopituitarism in hypophysitis: nonspecific destruction of all types of adenohypophysial cells by severe inflammation and selective destruction of specific adenohypophysial cells.

Alterations of haemostatic and fibrinolytic markers in adult patients with growth hormone deficiency and with acromegaly

Alterations of coagulation and fibrinolytic systems might contribute to the increased cardiovascular and cerebrovascular mortality observed in patients with both chronic growth hormone (GH) excess (acromegaly) and deficiency (GHD). However, contrasting results have been so far reported. To assess the importance of GH in modulating haemostatic system, several haemostatic variables in patients with GHD and acromegaly were measured. Twenty-four adult patients with GHD (8 childhood- and 16 adult-onset; age: 41+/-12 years, insulin like growth factor-I, IGF-I: 6.7+/-4 nmol/L), 10 non-diabetic acromegalic patients (age: 39+/-15 years; IGF-I: 109+/-37 nmol/L) and 64 healthy volunteers age- and sex-matched with cases were studied. The plasma levels of tissue-type plasminogen activator antigen (t-PA), prothrombin fragment 1+2 (F1+2) and thrombin-antithrombin complex (TAT) were measured by ELISA. Plasminogen activator inhibitor type I (PAI-1) was measured by an immunoactivity assay and fibrinogen by von Clauss method. GH levels were measured by IFMA and IGF-I by RIA. GHD patients had higher PAI-1 (12.7+/-16.7 vs 4.8+/-5.3 U/ml, p<0.01), fibrinogen (363+/-104 vs 291+/-71 mg/dL, p< 0.05) and TAT levels (6.8+/-9 vs 3.6+/-2.8 ng/ml, p<0.05) than controls. Taking the 95th pecentile of the normal distribution in the control group as the cut-off point for normal plasma levels of the haemostatic variables, high PAI levels were found in 25% of patients with GHD (P<0.01), while high fibrinogen and TAT levels were observed in 21% (P<0.05). The alterations were mostly present in patients with adult-onset GHD, with the exception of hyperfibrinogenaemia which was equally present in adult- and childhood-onset patients. Acromegalic patients had higher mean fibrinogen levels than controls (398+/-111 vs 291+/-71 mg/dL, p< 0.05), 40% having hyperfibrinogenaemia (P<0.01, vs controls). They also had t-PA levels lower than controls and GHD. No correlations between hormonal and haemostatic variables were found. Body mass index and waist to hip ratio correlated positively with PAI-1 levels in GHD patients only. In conclusion, this study shows that several abnormalities of coagulation variables (increased PAI-1. fibrinogen and TAT levels) are present in patients with GHD, while only hyperfibrinogenaemia is found in patients with acromegaly. These changes do not appear to be directly related to IGF-I levels or to the degree of GH deficiency/excess. However, these abnormalities may be an additional trigger for the development of coronary heart disease and thromboembolic complications mostly in patients with GHD.

Lymphocytic and granulomatous hypophysitis: experience with nine cases

OBJECTIVE

Lymphocytic hypophysitis and granulomatous hypophysitis are rarely encountered. The aim of this study was to demonstrate their clinical peculiarities among pituitary disorders and to provide an approach for their clinical management.

METHODS

In a retrospective study, we reviewed our surgical experience with nine patients harboring hypophysitis. The series included six cases of lymphocytic hypophysitis, two cases of granulomatous hypophysitis, and one case with evidence of coexisting lymphocytic and granulomatous hypophysitis.

RESULTS

A striking similarity of clinical signs was found for our nine patients. Headache or aseptic meningitis, thickening of the sphenoid sinus mucosa, pituitary stalk enlargement, and tongue-shaped extension of the lesion along the basal hypothalamus were characteristic signs. Lymphocytic hypophysitis was not associated with pregnancy in any of the seven cases. No recurrence has been observed in six cases with total removal of the inflammatory tissue.

CONCLUSION

Lymphocytic hypophysitis and granulomatous hypophysitis represent related inflammatory disorders. Their conspicuous clinical features frequently allow preoperative diagnosis of hypophysitis. In view of their sometimes insidious clinical course, early surgical exploration is justified.

Transsphenoidal treatment of non-neoplastic intrasellar cysts. A report of 38 cases

Thirty-eight patients underwent transsphenoidal microsurgical treatment of non-neoplastic intrasellar cysts: 36 had cyst drainage and biopsy of the cyst wall, and in two the cyst was totally removed. Surgical morbidity was 8%. The mean follow-up time was 46.3 months; 100% patient follow-up evaluation was achieved. Sixteen female patients (mean age 24.6 years) had pars intermedia cysts: 88% had menstrual irregularities, 63% had galactorrhea, 31% had headache, and 56% had hyperprolactinemia. Within these groups, menstrual cycles returned in 86%, galactorrhea ceased in 90%, headaches resolved in 80%, and serum prolactin levels were restored to normal in 66%. Eight females and three males had Rathke's cleft cysts (mean age 34.0 years): of these 11 patients, 91% had headaches and 18% had hyperprolactinemia; of the eight females, 63% had amenorrhea and 63% had galactorrhea. Within these groups, serum prolactin levels normalized in 50%, and 80% noted reduced headache. Of the females, 80% had return of menses and 50% noted cessation of galactorrhea. Six males and two females had arachnoid cysts (mean age 42.2 years): 50% had headaches; 50% were asymptomatic. Preoperatively, 50% of these patients had hypothyroidism and 25% had adrenal hypofunction. Postoperatively, 75% of patients with headache noted improvement, and 33% of patients with abnormal thyroid function had normal function. Adrenal function did not improve. Three patients had an intrasellar cysticercosis cyst, epidermoid cyst, and postoperative cyst, respectively. All had evidence of partial hypopituitarism; none improved postoperatively. The results indicate that different types of pituitary cysts produce different clinical syndromes, and suggest that simple transsphenoidal drainage and partial removal of the cyst wall can provide safe and effective therapy.

Histological classification of pituitary disease

Morphological features of pituitary disease are classified according to increased and decreased hormone production to allow clinical correlation with pathological processes. Increased hormone synthesis and secretion may be due to pituitary adenomas or carcinomas derived from the five hormone-secreting cell types, or to extrapituitary stimuli causing hypertrophy and hyperplasia of those cells. Various tumour-like conditions can mimic functioning adenomas. Rarely, no lesion is detected and intrinsic abnormalities of adenohypophyseal cells are implicated. Hypopituitarism can be selective or generalized. Diffuse hormone deficiency is usually attributable to tissue destruction by tumours, inflammatory or infiltrative conditions or vascular lesions. Congenital abnormalities of pituitary development may result in hypophyseal dysfunction. Hypothalamic abnormalities may cause generalized hypopituitarism or may involve only selective releasing factors and hormones. Feedback inhibition and receptor abnormalities may be implicated in pituitary hypofunction, and selective deficiencies may be the result of genetic abnormalities, immune reactions or toxic damage to one cell type.