Therapeutic Response to Rituximab in IgG4-Related Hypophysitis Evidenced on 18F-FDG PET and MRI

AuntMinnie Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography Leads to Diagnosis of Immunoglobulin G4-Related Disease

A 61-year-old male underwent fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) for evaluation of fever and weight loss with clinical suspicion of occult malignancy or tuberculosis. The scan showed hypermetabolism in bilateral submandibular salivary glands, biliary radicles, pancreas, bilateral kidneys, prostate, and multiple lymph nodes. Based on the concomitant involvement of these sites, suspicion of immunoglobulin G4 (IgG4)-related disease was raised in PET-CT report. Further evaluation with serum IgG4 levels and histopathology of the submandibular salivary gland confirmed the diagnosis of IgG4-related disease. The ability of FDG PET-CT to evaluate the whole-body status of disease played a crucial role in this case.

Hypophysitis: A comprehensive overview

Hypophysitis is defined as inflammation of the pituitary gland. It is a heterogeneous condition as it can originate from different parts of the pituitary gland, can be caused by different pathophysiological processes, and can be isolated or the manifestation of a underlying systemic disease. Hypophysitis usually presents with endocrine deficiencies, including diabetes insipidus, with varying patterns. A subset of patients presents with mass effects. The last decades major progress has been made in the understanding of this disease. New forms are now recognized, new diagnostics are being developed, and specific treatments are proposed. This review provides an overview of the current knowledge on hypophysitis using an aetiology-based approach and provides the clinician with a stepwise approach to the patient with (suspected) hypophysitis.

Gonadotropin-Secreting Pituitary Macroadenoma Complicated With Hemorrhagic Apoplexy in 18F-FDG PET/CT

ABSTRACT

We report the case of 69-year-old man referred for a stage IV pulmonary adenocarcinoma and presenting a decrease in visual acuity. An 18F-FDG PET/CT showed an intense and heterogeneous uptake of a mass in the sellar region. An MRI showed a pituitary macroadenoma associated with a large cyst on the left side, with necrosis zones and fluid level, compressing the optic chiasma. Endocrine testing showed a panhypopituitarism, and pathology confirmed a pituitary apoplexy in a gonadotropin-secreting macroadenoma. No malignant cells were detected. Molecular imaging could have an important role in the detection and characterization of pituitary tumors.

IgG4-related hypophysitis

Hypophysitis is a rare pituitary inflammatory disorder classified in different ways. Immunoglobulin G4-related disease (IgG4-RD), also a rare disease is a systemic fibro-inflammatory condition characterized by infiltration of tissue with IgG4-positive plasma cells; however prevalence of both of them probably is underestimated. In this paper, we present an Iranian patient with biopsy-proven IgG4-related hypophysitis and then review the clinical characteristics, laboratory, imaging, pathologic findings and therapeutic management as well as prognosis of 115 published cases of hypophysitis secondary to IgG4-related disease.

Pituitary Metastases Discovered by 18F-FDG PET/CT During Other Cancers Monitoring: Are There Any Differences of SUVs Between Benign and Malignant Diseases?

F-FDG PET/CT might discover incidental pituitary lesions. We present the case of a 46-year-old woman with breast cancer metastasis in her pituitary. We analyzed 10,347 FDG PET/CT examinations from a tertiary center, finding 4 cases (0.038%) of pituitary metastatic disease from other cancers. We analyzed the differences between SUVmax in cases of physiological high uptake, primary tumor, and hypophysis metastases from other cancers in our database compared with the literature.

Clinical Characteristics of 76 Patients with IgG4-Related Hypophysitis: A Systematic Literature Review

BACKGROUND

IgG4-related hypophysitis (IgG4-RH) is a rare disease, and its prevalence remains unclear. In recent years, an increasing number of cases have been reported because of the increasing recognition of this disease. We aimed to summarize case reports of IgG4-RH and outline the clinical features and outcomes.

METHODS

We performed PubMed search of articles using the search terms "hypophysitis [AND] IgG4." Consequently, only 54 English articles (76 cases) met Leporati's diagnostic criteria.

RESULTS

Of the 76 cases, the ratio of men to women was 1.5 : 1, and the age at diagnosis was 54.1 ± 17.8 years. The median IgG4 concentration was 405.0 mg/dl. Anterior hypopituitarism, isolated central diabetes insipidus, and panhypopituitarism were observed in 14 (18.4%), 12 (15.8%), and 44 (57.9%) cases, respectively. The sequence of anterior hormone deficiency was as follows: gonadotropin (68.4%), ACTH (63.2%), TSH (59.2%), GH (48.7%), and prolactin (42.1%). The median number of involved organs was 1.5, and the lung (18.4%), retroperitoneum (17.1%), kidney (15.8%), submandibular glands (14.5%), and pancreas (13.2%) were the common involved organs. Elevated IgG4 concentration and normal IgG4 level were in 42 (76.4%) and 13 (23.6%) cases, respectively. Patients with elevated serum IgG4 concentration were older (60.9 ± 14.3 vs 45.6 ± 17.4, p=0.001) and male-prone (78.6% vs 40.4%, p=0.003) and had a susceptibility of multiple organ involvement (78.6% vs 35.0%, p=0.001) compared to those with normal serum IgG4 levels. Males were older at disease onset (61.5 ± 12.6 vs 42.9 ± 18.8, p < 0.001) and had a higher IgG4 concentration (425.0 vs 152.5, p=0.029) and a greater number of involved organs (2.0 vs 0.0, p=0.001), while isolated hypophysitis was more prominent in female (63.3% vs 26.1%, p=0.001).

CONCLUSION

In this review, we found that there were different characteristics between different genders. Patients with elevated serum IgG4 level in terms of some clinical features were also different from those with normal serum IgG4 level. However, the data in this review were limited by bias and confounding. Further clinical studies with larger sample sizes are warranted.