Autoimmune Pancreatitis—Prototype of IgG4-related Sclerosing Disease

Primary cutaneous Rosai-Dorfman disease; a case-based review of a diagnostically and therapeutically challenging rare variant

Primary cutaneous Rosai-Dorfman disease is a rare form of Rosai-Dorfman disease limited to the skin. The diagnosis of primary cutaneous disease is based on a combination of clinical presentation, histopathology, and the detection of S100+, CD68+, and CD1a- histiocytic immunophenotyping. However, the diagnosis of primary cutaneous disease is often difficult and significantly delayed due to the non-specific nature of its histologic and clinical features. In this review, we describe four cases in order to familiarize pathologists and dermatopathologists with the clinicopathologic correlation of primary cutaneous Rosai-Dorfman disease and to help facilitate early diagnosis. In addition, we discuss the proposed pathophysiology and molecular etiology of this tumor, and its relationship with IgG4 sclerosing disease.

Sclerosing angiomatoid nodular transformation of the spleen (SANT): clinicopathological study of 10 cases with or without abdominal disseminated calcifying fibrous tumors, and the presence of a significant number of IgG4+ plasma cells

Sclerosing angiomatoid nodular transformation (SANT) is a peculiar splenic vascular lesion that is characterized by marked stromal sclerosis and the presence of plasma cells, which shares histopathological features associated with IgG4-related sclerosing disease. The cinicopathological features of 10 cases of SANT were reviewed and immunohistochemistry with IgG4 and IgG antibodies was performed. Nine other various splenic lesions served as controls. Five cases of SANT were found incidentally. Three cases of SANT had multiple tumors and five had associated abdominal disseminated calcifying fibrous tumors (CFT). IgG4+ plasma cells were found in all of the cases of SANT and in calcifying fibrous tumors. The densities of IgG4+ and IgG+ cells and the IgG4/IgG ratios were significantly higher in SANT than in control spleens (P= 0.001, 0.006, and 0.028, respectively). Serum IgG4 concentration was elevated in one case. In conclusion, SANT can occur either as a solitary or as multiple tumors. Frequent association with abdominal disseminated CFT simulating carcinomatosis was observed. A statistically significant number of IgG4+ plasma cells was found in all of the cases of SANT and the associated CFT. Whether they are related to the IgG4-related sclerosing disease or not is debatable and warrants further investigation.

IgG4-related sclerosing mastitis: description of a new member of the IgG4-related sclerosing diseases

Immunoglobulin G (IgG)4-related sclerosing disease is a recently described syndrome characterized by mass-forming lesions in various organs due to dense lymphoplasmacytic infiltrates and stromal sclerosis, elevated serum IgG4 titer, increased tissue IgG4 plasma cells, and favorable clinical outcome. We describe 4 patients with IgG4-related sclerosing mastitis, which represents a new member of this family of diseases. All patients were female with a mean age of 47.5 years, presenting with painless masses in 1 or both breasts. One patient had concurrent IgG4-related lymphadenopathy, and another had eyelid swelling of undetermined cause. The serum IgG4 titer was elevated in 1 tested patient, and circulating autoantibodies were found in 3 tested patients. All patients were well with no recurrence after excision or biopsy of the mass. Histologically, the breast masses featured dense lymphoplasmacytic infiltrates, prominent stromal sclerosis and loss of breast lobules. Phlebitis was present in 1 case. IgG4 cells ranged from 272 to 495 per high-power field, constituting 49% to 85% of all IgG cells. IgG4 cells were scarce in 9 of 9 cases of lymphocytic mastitis and 6 of 7 cases of granulomatous mastitis studied as controls. In summary, IgG4-related sclerosing mastitis appears to be a distinctive form of mastitis, sometimes accompanied by other components of IgG4-related sclerosing disease, and shows a favorable clinical outcome.

IgG4-related sclerosing pachymeningitis: a previously unrecognized form of central nervous system involvement in IgG4-related sclerosing disease

IgG4-related sclerosing disease is a distinctive mass-forming lesion with frequent systemic involvement, most frequently the pancreas, salivary glands, and lacrimal glands. This report describes a case manifesting with a previously unrecognized form of central nervous system involvement. The 37-year-old man presented with signs and symptoms of spinal cord compression at the thoracic level 9. Magnetic resonance imaging revealed an elongated dural mass extending from the fifth to tenth thoracic vertebra. Laminectomy and excision of the mass revealed dura expanded by a dense lymphoplasmacytic infiltrate accompanied by stromal fibrosis and phlebitis. IgG4+ plasma cells were increased and the proportion of IgG4+/IgG+ plasma cells was 85%. The patient also had a 1-year history of bilateral submandibular swelling due to chronic sialadenitis. Thus, IgG4-related sclerosing pachymeningitis represents a new member of the IgG4-related sclerosing disease family affecting the central nervous system. It seems that at least a proportion of cases described in the literature as idiopathic hypertrophic pachymeningitis belong to this disease, especially as some patients have other clinical manifestations compatible with IgG4-related sclerosing disease, such as cholangitis and orbital pseudotumor.

Simultaneous Occurrence of IgG4-Related Chronic Sclerosing Dacryoadenitis and Chronic Sclerosing Sialadenitis Associated with Lymph Node Involvement and Warthin’s Tumor

Chronic sclerosing dacryoadenitis and chronic sclerosing sialadenitis have been shown to belong to the group of diseases referred to as IgG4-related sclerosing disease. The authors report a case of the simultaneous occurrence of IgG4-related sclerosing disease in both lacrimal and submandibular glands, clinically simulating malignant lymphoma. A cervical lymph node and a Warthin’s tumor were also involved. This unique case of multiple organ involvement in IgG4-related sclerosing disease is documented.

Lymphadenopathy of IgG4-related sclerosing disease

IgG4-related sclerosing disease is a recently recognized syndrome characterized by mass-forming lesions in exocrine glands or extranodal tissues due to lymphoplasmacytic infiltrates and sclerosis, a raised serum IgG4 level and increased IgG4+ plasma cells in the involved tissues. We report the morphologic features of the enlarged regional (n=3) and nonregional lymph nodes (n=3) in patients with this syndrome. The patients presented with autoimmune pancreatitis, lymphoplasmacytic sclerosing cholangitis, chronic sclerosing dacryoadenitis, or chronic sclerosing sialadenitis. The histologic features of the lymph nodes could be categorized into 3 patterns: Castleman diseaselike, follicular hyperplasia, and interfollicular expansion by immunoblasts and plasma cells. The percentage of IgG4+/IgG+ plasma cells was markedly elevated (mean 62% vs. 9.9% in 54 control lymph nodes comprising a wide variety of reactive conditions). We also report 6 cases of primary lymphadenopathy characterized by increased IgG4+/IgG+plasma cells (mean 58%). These cases share many clinical and pathologic similarities with IgG4-related sclerosing disease. In fact, 2 of these patients developed lymphoplasmacytic sclerosing cholangitis or lacrimal and submandibular gland involvement during the clinical course. These cases therefore probably represent primary lymph node manifestation of the disease. The importance of recognition of the lymphadenopathic form of IgG4-related sclerosing disease lies in the remarkable response to steroid therapy, and the potential of mistaking the disease for lymphoma either clinically or histologically.

Advances in salivary gland pathology

This review summarizes the new findings on salivary gland pathology under the following categories: immunohistochemistry; molecular genetics; newly recognized tumour types; known tumour entities with new findings; and progression of salivary gland tumours. In the application of immunohistochemistry, CD117 can aid in highlighting the luminal cell component of various salivary gland tumours, whereas p63 or maspin can aid in highlighting the abluminal cell component. A high Ki67 index remains the most useful marker to predict adverse outcome in salivary gland carcinoma. Specific chromosomal translocations are recognized in pleomorphic adenoma (with translocation involving PLGA1 or HMGA2 gene) and mucoepidermoid carcinoma (with MECT1-MAML2 gene fusion). Newly recognized entities include: sclerosing polycystic adenosis (with recent molecular evidence supporting its neoplastic nature), sclerosing mucoepidermoid carcinoma with eosinophilia, keratocystoma, adenoma with additional stromal component (lymphadenoma, lipoadenoma and adenofibroma), cribriform adenocarcinoma of the tongue and signet ring adenocarcinoma of minor salivary gland. Known tumour entities with new findings include: salivary duct carcinoma (with newly recognized mucinous, micropapillary and sarcomatoid variants), intraductal carcinoma (with controversies in terminology), mucoepidermoid carcinoma (with newly proposed grading parameters and oncocytic variant), epithelial-myoepithelial carcinoma (with newly recognized morphological variants), small cell carcinoma (with most cases being related to Merkel cell carcinoma), extranodal marginal zone B-cell lymphoma (with specific chromosomal translocation) and chronic sclerosing sialadenitis (being a component of IgG4-related sclerosing disease). Progression of salivary gland tumours can take the form of malignant transformation of a benign tumour, progression from low-grade to high-grade carcinoma, dedifferentiation, or stromal invasion of an in situ carcinoma.