IgG4-Associated Adrenalitis-a Case Report

Inflammatory and Infectious Disorders in Endocrine Pathology

A variety of inflammatory conditions may directly involve the endocrine glands, leading to endocrine dysfunction that can cause severe consequences on patients' health, if left untreated. Inflammation of the endocrine system may be caused by either infectious agents or other mechanisms, including autoimmune and other immune-mediated processes. Not infrequently, inflammatory and infectious diseases may appear as tumor-like lesions of endocrine organs and simulate neoplastic processes. These diseases may be clinically under-recognized and not infrequently the diagnosis is suggested on pathological samples. Thus, the pathologist should be aware of the basic principles of their pathogenesis, as well as of their morphological features, clinicopathological correlates, and differential diagnosis. Interestingly, several systemic inflammatory conditions show a peculiar tropism to the endocrine system as a whole. In turn, organ-specific inflammatory disorders are observed in endocrine glands. This review will focus on the morphological aspects and clinicopathological features of infectious diseases, autoimmune disorders, drug-induced inflammatory reactions, IgG4-related disease, and other inflammatory disorders involving the endocrine system. A mixed entity-based and organ-based approach will be used, with the aim to provide the practicing pathologist with a comprehensive and practical guide to the diagnosis of infectious and inflammatory disorders of the endocrine system.

The external validation of the 2019 ACR/EULAR classification criteria for IgG4-related disease in a large cohort from China

OBJECTIVE

To externally validate the performance of the 2019 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) classification criteria for IgG4-related disease (IgG4-RD) within a cohort from China and to compare the criteria with the 2020 revised comprehensive diagnostic (RCD) criteria for IgG4-RD.

METHODS

This study included 875 IgG4-RD and 302 non-IgG4-RD cases (213 mimickers and 89 patients with other diseases). Using expert clinical judgment as the gold standard for diagnosis of IgG4-RD, the performance (sensitivity, specificity, area under the curve (AUC) of the 2019 ACR/EULAR criteria for IgG4-RD was evaluated. We also compared it with the 2020 RCD criteria.

RESULTS

The 2019 ACR/EULAR classification criteria had a sensitivity of 76.6% (95% CI: 73.8% to 79.4%) and a specificity of 98.0% (96.0%-99.4%), an AUC of 0.873 (0.857-0.889) in the overall cohort. Those false negative cases under the 2019 ACR/EULAR classification criteria had significantly lower levels of serum IgG4, and fewer had pathological information, with a higher frequency in the involvement of those uncommon organs compared with the true positive cases. The cases judged as negative by the 2019 ACR/EULAR classification criteria yet judged as "definite" by the 2020 RCD criteria had more involvement of uncommon organs.

CONCLUSIONS

The 2019 ACR/EULAR classification criteria for IgG4-RD show outstanding specificity and good sensitivity in real-world clinical practice. The 2020 RCD criteria are helpful for the diagnosis of IgG4-RD in clinical scenarios where IgG4-RD presents as involving an isolated organ, especially the unusual sites.

Clinicopathologic Study of Calcifying Fibrous Tumor Emphasizing Different Anatomical Distribution and Favorable Prognosis

Aims

Calcifying fibrous tumor (CFT) is a very rare begin fibroblastic tumor featuring a widely anatomical distribution and may mimic various spindle cell tumors. Misdiagnosis and hence mistreatment are likely caused due to unfamiliarity to clinicians or junior pathologists. We collected a relatively large series of CFTs in our institution aiming at further summarizing their clinicopathologic features in Chinese patients and discussing the diagnosis and differential diagnosis in clinical practice.

Methods

Clinicopathologic data of 22 CFTs were retrospectively reviewed. Histologic features were reevaluated and summarized. Immunostaining markers include CD34, SMA, Desmin, keratin, S100, ALK1, CD117, IgG, IgG4, and Ki-67. Follow-up of all cases was performed.

Results

22 CFTs include gastric (n=8), pulmonary (n=2), hepatic (n=2), cervical (n=1), appendiceal (n=1), esophageal (n=1), retroperitoneal (n=1), intra-abdominal (n=1), diaphragmatic (n=1), spermatic cord and scrotum (n=1), anconeal (n=1), mesenteric (n=1), and omental (n=1) lesions. Coexisting hepatocellular carcinoma, pancreatic carcinoma, pheochromocytoma, Castleman disease, and leiomyoma of the uterus and other metabolic or functional disorders were also appreciated. CFT histologically features spindle cells embedded dense hyalinized stroma with scattered psammomatous calcifications and lymphoplasmacytic infiltration and immunohistochemically for CD34. None of any individuals die of CFT per se.

Conclusion

Our study discloses that CFT is a bona fide benign fibroblastic lesion, regardless of its developing location. Involvement of digestive tract seems much more common in the Chinese population. Awareness of the clinicopathologic characteristics of this rare entity and its mimickers contribute to avoiding misdiagnosis and mistreatment in clinical practice.