Rosai-Dorfman Disease of the Breast With Variable IgG4+ Plasma Cells: A Diagnostic Mimicker of Other Malignant and Reactive Entities

Rosai-Dorfman disease of the breast: a clinicoradiologic and pathologic study

Rosai-Dorfman disease (RDD) is an uncommon histiocytic disorder typically involving lymph nodes and less frequently extranodal tissues. RDD involving the breast is rare and may clinically and radiologically mimic neoplastic and non-neoplastic disorders. We report seven patients with breast RDD, describe their clinicoradiologic and pathologic features, and discuss the differential diagnosis. Patients, ranging from 15 to 74 years of age, presented with unilateral and unifocal (5/7) or bilateral and multifocal (2/7) masses. RDD was either confined to the breast (6/7) or concurrently involved a lymph node (1/7). Masses ranged from 8 to 31 mm, categorized as Breast Imaging-Reporting and Data System (BI-RADS) 4 (6/7) or 5 (1/7). All cases showed similar morphology with many large histiocytes displaying emperipolesis with associated fibrosis and dense lymphoplasmacytic infiltrate. The abnormal histiocytes co-expressed CD68/CD163, S100, OCT2, and Cyclin D1 (7/7), and were negative for CK AE1/AE3 (7/7), CD1a (7/7), and BRAF V600E (6/6). Flow cytometry (n = 3), kappa/lambda in situ hybridization (n = 5), and IgG4/IgG immunohistochemistry (n = 1) did not reveal lymphoma or IgG4-related disease. No mycobacterial or fungal organisms were identified on acid-fast bacillus (AFB) and Grocott methenamine silver (GMS) stains (n = 5). Three patients underwent complete excision and none recurred or progressed to systemic disease during follow-up (88-151 months). In summary, breast RDD should be included in the differential diagnosis of a mass-forming breast lesion. Histopathology with ancillary studies and clinicoradiologic correlation is essential for accurate diagnosis and optimal clinical management. Patients with RDD of the breast have an excellent prognosis after complete excision.

Primary Bilateral Intraosseous Rosai-Dorfman Disease

Rosai-Dorfman disease (RDD) is a rare histiocytic proliferative disease of unknown etiology. Typically presenting with cervical adenopathy and constitutional symptoms, RDD involves bone in less than 10% of cases-and rarely presents as a primary intraosseous lesion. In this report, we describe the presentation of primary, bilateral intraosseous RDD, the first known case in the literature. Asymmetrically involving the lateral femoral condyles of a 59-year-old male, the lesion was discovered incidentally during evaluation and workup for giant cell tumor of bone involving the left tibia. Confirmation of the diagnosis required multiple biopsies and extensive evaluation-reflecting the diagnostic challenge associated with this case. We discuss the clinical, radiological, and pathological findings that allowed us to establish the diagnosis-as well as key differential diagnostic considerations and clinical outcome to date.

Inflammatory Lesions of the Breast

CONTEXT.—

Inflammatory lesions of the breast are rare but not infrequently pose problems both clinically and morphologically, particularly on needle core biopsies. These lesions range from acute inflammatory conditions to chronic lymphoplasmacytic and lymphohistiocytic to granulomatous inflammatory diseases.

OBJECTIVE.—

To provide a comprehensive overview of inflammatory lesions of the breast, with etiopathogenesis and clinical, radiologic, and pathologic features as well as differential diagnostic considerations, clinical management, and prognosis.

DATA SOURCES.—

The existing literature in the English language, including original research articles and review articles describing inflammatory lesions of the breast.

CONCLUSIONS.—

Inflammatory lesions of the breast are characterized by a wide variety of clinical, radiologic, and morphologic features. The histopathologic differential diagnosis often includes a neoplastic process requiring ancillary studies and correlation with clinical and radiologic findings. Although most specimens display nonspecific findings precluding a definitive pathologic diagnosis, pathologists have a unique opportunity to play a crucial role in identifying key histologic features suggestive of certain entities, such as cystic neutrophilic granulomatous mastitis, immunoglobulin (Ig) G4 mastitis, or squamous metaplasia of lactiferous ducts, in the right clinical and radiologic context, and thereby guiding optimal and timely clinical management. The information presented herein will be helpful to practicing anatomic pathologists and pathology trainees in becoming more familiar with specific morphologic features and overcoming differential diagnostic challenges related to pathology reporting of inflammatory lesions of the breast.

Primary intraosseous Rosai-Dorfman disease: An analysis of clinicopathologic characteristics, molecular genetics, and prognostic features

Background

Rosai-Dorfman disease (RDD) is a rare histiocytic proliferative disorder of uncertain pathogenesis. Most patients present with proliferation in the lymph nodes manifesting as adenopathy; however, RDD may primarily arise in a variety of extranodal sites, including the bone, which is a great challenge in the diagnosis. The clinicopathological characteristics and prognostic features of primary intraosseous RDD have not been well characterized.

Methods

We retrospectively analyzed the clinicopathologic and prognostic features of four cases of primary intraosseous RDD during the past 10 years in our hospital, with a review of an additional 62 cases with complete follow-up data from the literature.

Results

Primary intraosseous RDD was identified in 0.14% (4/2,800) of total bone biopsies performed at our institution over the study period. According to our retrospective analysis, a total of 18 cases of primary lymph node, skin, or other non-osseous site-based RDD were diagnosed in our hospital. The ages of the 66 total patients ranged from 1.5 to 76 years, with a median age of 25 years. There were 31 male and 35 female patients, with a male-to-female ratio of 0.89:1. Primary intraosseous RDD occurred most often in the bones of the extremities (60.6%, 40/66), with the proximal tibia being the most common location; 39.4% (26/66) of the cases arose in the axial skeleton, predominantly in the vertebra and craniofacial bones. Solitary masses and multiple tumors were present in 84.8% (56/66) and 15.2% (10/66) of the cases, respectively. Pain of the affected area was the most common presenting symptom. Radiographically, the lesions were lytic with well-defined and usually sclerotic margins. Immunohistochemistry showed that large histiocytes from patients with RDD were positive for OCT2, in addition to S100 and CD68. Molecular tests were performed in seven reported cases and four of our cases. All the 11 cases were non-decalcified. PCR results showed that there were no BRAF-V600E, KRAS, or NRAS mutations in primary intraosseous RDD; only one case with both RDD and Langerhans cell histiocytosis showed BRAF-V600E mutation. The survival data showed that 22.7% (15/66) of the patients experienced recurrences or developed RDD at distant sites during the follow-up period (median follow-up, 13 months; range, 1-106 months). The 5-year progression-free survival (PFS) of the patients with primary intraosseous RDD was 57.5%. We found that there was a significant difference in PFS between female and male patients (p = 0.031). However, there was no statistically significant difference in PFS between patients with solitary masses and multiple tumors (p = 0.698). Similarly, no statistically significant differences in PFS were found between the different age groups (p = 0.908) or tumor locations (p = 0.728).

Conclusion

Primary intraosseous RDD is an extremely rare disease. The diagnosis of RDD may be quite challenging because of its non-specific clinical presentation and imaging. Immunohistochemistry showed that large histiocytes were positive for OCT2 in addition to S100 and CD68, which may be helpful for differential diagnosis. Molecular detection showed that RDD may be related to the MAPK pathway, though these results are also ultimately not specific. The pathogenesis of RDD is yet to be elucidated, but recent studies suggest possible clonality of hyperproliferative histiocytes.

Acute Tubulointerstitial Nephritis in Rosai-Dorfman Disease Mimicking IgG4-related Disease

Rosai-Dorfman-Destombes disease (RDD) is a non-Langerhans cell histiocytosis characterized by the accumulation of histiocytes inside the lymph nodes or extranodally. The association between RDD and IgG4-related disease (IgG4-RD) is discussed. We herein report a case of RDD manifesting as acute tubulointerstitial nephritis mimicking IgG4-RD. The first renal biopsy showed severe tubulointerstitial nephritis with infiltration of S100-positive histiocytes and IgG4-positive plasma cells; storiform fibrosis and obliterative phlebitis were not confirmed. After prednisolone therapy, IgG4-positive cells and S100-positive histiocytes were decreased, but the IgG4/IgG ratio increased despite clinical improvement. These findings indicated extranodal RDD in the kidney presenting as tubulointerstitial nephritis.

Distinct Clinicopathologic Features and Possible Pathogenesis of Localized ALK-positive Histiocytosis of the Breast

Anaplastic lymphoma kinase (ALK)-positive histiocytosis is a rare emerging entity characterized by systemic or localized proliferation of histiocytes harboring ALK rearrangements. Breasts are reportedly affected by ALK-positive histiocytosis. Here, we evaluated 2 localized cases of breast ALK-positive histiocytosis through a comprehensive clinicopathologic, molecular, and genomic analysis to further delineate this entity and better understand its pathogenesis. The cases involved 2 undiagnosed ALK-positive spindle-cell breast lesions. Both cases were Asian women aged 30s to 40s who underwent excisions for asymptomatic breast masses. Macroscopically, both lesions were well-circumscribed, solid masses. Microscopically, both lesions were predominantly composed of fascicles with uniform, bland spindle cells, admixed with epithelioid histiocyte-like cells and lymphoid aggregates. Immunohistochemically, the spindle and epithelioid cells coexpressed ALK and histiocytic markers (eg, CD68, CD163). Genetically, both lesions harbored KIF5B-ALK, confirmed by fluorescence in situ hybridization and polymerase chain reaction-direct sequencing analyses. Combining these results, both cases were successfully diagnosed as ALK-positive histiocytosis. Furthermore, no common or previously annotated somatic alterations were identified by whole-exome sequencing. One case harbored clonal immunoglobulin gene rearrangements according to the polymerase chain reaction-based BIOMED-2 protocol. Therefore, ALK-positive histiocytosis can be accurately diagnosed through a combination of morphologic, immunohistochemical, and molecular analyses. In this entity, breast cases may have distinct clinicopathologic features: Asian women aged 30s to 40s, asymptomatic masses, and predominant spindled morphology. For pathogenesis, ALK rearrangements could be the driver alteration, and a subset of ALK-positive histiocytosis may harbor a lymphoid lineage. These findings can be utilized to improve the diagnosis of ALK-positive histiocytosis and better understand its pathogenesis.

Rosai–Dorfman Disease: Breast Involvement—Case Report and Literature Review

Background and objectives: Rosai–Dorfman disease (RDD) is a type of histiocytosis that usually appears in young adults or children as bilateral cervical lymphadenopathy, but extranodal involvement in not uncommon. Although the pathogenesis is not entirely elucidated, recent studies showed a possible neoplastic process. Materials and methods: Our manuscript presents a rare case of Rosai–Dorfman disease of the breast, the management of this rare case, and a literature review. There are few cases reported of RDD of the breast (around 90 globally reported cases); the data is poor, and the management not yet standardized for these cases. The case reported here shows the importance of correct breast investigation, breast imaging, and ultrasound-guided biopsy that provided an accurate diagnosis and guided further management. Results: Although RDD of the breast was rarely presented as bilateral disease in other case reports, our case showed bilateral breast disease with the suspicion of breast cancer on imaging. Pathology and immunohistochemistry were of critical importance and showed a specific pattern for histiocytosis. A multidisciplinary approach was taken into consideration for these cases in order to establish the approach. Some patients underwent surgery, but watchful waiting and close follow-up were the preferred approach. Conclusions: RDD of the breast is a rare form of histiocytosis, with fewer than 100 globally published cases. Although the management of this disease is not established yet by guidelines, a follow-up approach should be enough for these patients, and surgery might be overtreatment. Mortality from RDD is very low due to comorbidities. A multidisciplinary team decision is important, and abstinence might significantly benefit these patients.

Combining contrast-enhanced ultrasound and blood cell analysis to improve diagnostic accuracy of plasma cell mastitis

Plasma cell mastitis is a benign suppurative disease of the breast, lack of specific clinical manifestations, which is easy to be misdiagnosed and mistreated, often confused with mastitis, breast cancer (BC), and other diseases. Thus, we aimed to establish a combined model of promoting diagnostic accuracy of plasma cell mastitis by contrast-enhanced ultrasound (CEUS) patterns and routine blood cell analysis. Eighty-eight plasma cell mastitis, 91 breast cancer, and 152 other benign breast diseases' patients grouped according to pathological diagnosis underwent CEUS and blood cell analysis examination; 100 healthy female donors were involved. All the plasma cell mastitis and breast cancer patients presented hyperenhancement of CEUS breast lesions compared with others. The majority of plasma cell mastitis (65/88) showed perfusion defect of CEUS patterns with smooth edge (56/65) and multiple lesions (49/65); in contrast, fewer breast cancer patients (30/91) displayed perfusion defect. White blood cell count (WBC), neutrophils, and neutrophils/lymphocytes ratio of blood cell analysis in plasma cell mastitis patients increased significantly compared with other patients (P < 0.0001). Combining perfusion defect of CEUS patterns and WBC yielded an area under the receiver operating characteristic curve of 0.831, higher than single 0.720 and 0.774, respectively. The cut-off value of WBC (7.28 × 10⁹/L) helped remaining 65.2% (15/23) atypical cases to be correctly diagnosed as plasma cell mastitis, not misdiagnosed as breast cancer. In conclusion, CEUS presented a clear perfusion defect pattern of plasma cell mastitis lesion for the first time. A precise WBC by routine blood cell analysis test can assist CEUS examination in the differential diagnosis of plasma cell mastitis and breast cancer. It is a promised combination for laboratory diagnostic of PCM.

ALK-positive Histiocytosis of the Breast: A Clinicopathologic Study Highlighting Spindle Cell Histology

Originally described as a systemic self-limiting disease in infancy, the spectrum of ALK-positive histiocytosis has recently been broadened to include localized diseases in older children and young adults. Despite different manifestations, these tumors share histologic characteristics and a highly recurrent KIF5B-ALK fusion. ALK-positive histiocytosis is poorly characterized in the breast. In this study, we report 3 cases of ALK-positive histiocytosis of the breast. The patients were Asian women, aged 16 to 45 years. Two patients presented with an isolated breast mass, while 1 exhibited multiorgan involvement. The latter patient received ALK inhibitor after surgery, which led to complete remission. Histologically, well-circumscribed tumors displayed fascicular and storiform growth of uniform, nonatypical spindle cells admixed with lymphocytic infiltrates. Fewer conventional epithelioid histiocytes with lobulated or clefted nuclei were observed within the same breast tumors in 2 cases or within a concomitant brain tumor in the third case. Touton-type giant cells were focally present in 2 cases. Immunohistochemically, tumor spindle, and epithelioid cells were diffusely positive for CD163 and ALK in all cases and focally positive for S100 protein in 1 of the cases. CD1a and langerin were negative. Actin-positive myofibroblasts were admixed within the tumor in 2 cases, and their reactive nature was highlighted using double immunostaining. Break-apart fluorescence in situ hybridization assay demonstrated gene rearrangements involving KIF5B and ALK in all the 3 cases. ALK-positive histiocytosis rarely occurs as a spindle cell breast tumor, and should be distinguished from other diseases such as inflammatory myofibroblastic tumors and spindled histiocytic reaction.

Rosai-Dorfman Disease Displays a Unique Monocyte-Macrophage Phenotype Characterized by Expression of OCT2

Rosai-Dorfman disease (RDD) is a rare histiocytosis with heterogenous clinical features. In this study, we characterized the histologic and phenotypic features in 33 RDD patients to better define the pathologic diagnosis. Cases included 24 patients with extracutaneous disease ("R" group), and 9 patients with lesions limited to the skin or subcutaneous tissue ("C" group). We identified OCT2 as a novel marker for the monocyte-macrophage phenotype of RDD, expressed in 97% of RDD cases. In contrast, OCT2 expression was seen in 0% of Erdheim-Chester disease cases and 6.7% of Langerhans cell histiocytosis cases. Other markers useful in the diagnosis of RDD included S100 (100%), CD163 (88%), and cyclin D1 (97%). In a subset of cases, RDD showed moderate to strong expression of factor 13a (30%), p16 (64%), and phosphorylated extracellular signal-regulated kinase (45%); RDD was uniformly negative for ZBTB46, CD1a, and langerin. Within the "R group" of RDD, increased expression of factor 13a or phosphorylated extracellular signal-regulated kinase showed a statistically significant association with multifocal disease (P<0.05). Identification of the unique monocyte-macrophage phenotype of RDD with OCT2 expression furthers our understanding of this complex disease and allows for more uniform classification.

Pathology of IgG4-related sclerosing mastitis

Immunoglobulin G4-related sclerosing mastitis (IgG4-RM) is a recently recognised member of the IgG4-related disease (IgG4-RD) family, a multisystem fibroinflammatory condition that can affect any organ system. IgG4-RM is rare and predominantly occurs in middle-aged women. It may present with painless palpable mass and/or lymphadenopathy thereby mimicking breast cancer. Although there is an abundance of literature describing the clinicopathological characteristics of IgG4-RD in a variety of organs, data on IgG4-RM are limited due to its rarity. This review describes the manifestation of the disease in the breast based on reported cases, emphasising the clinicopathological features, pathophysiology, differential diagnosis, treatment and prognosis.

Steroid Therapy and Steroid Response in Autoimmune Pancreatitis

Autoimmune pancreatitis (AIP), a unique subtype of pancreatitis, is often accompanied by systemic inflammatory disorders. AIP is classified into two distinct subtypes on the basis of the histological subtype: immunoglobulin G4 (IgG4)-related lymphoplasmacytic sclerosing pancreatitis (type 1) and idiopathic duct-centric pancreatitis (type 2). Type 1 AIP is often accompanied by systemic lesions, biliary strictures, hepatic inflammatory pseudotumors, interstitial pneumonia and nephritis, dacryoadenitis, and sialadenitis. Type 2 AIP is associated with inflammatory bowel diseases in approximately 30% of cases. Standard therapy for AIP is oral corticosteroid administration. Steroid treatment is generally indicated for symptomatic cases and is exceptionally applied for cases with diagnostic difficulty (diagnostic steroid trial) after a negative workup for malignancy. More than 90% of patients respond to steroid treatment within 1 month, and most within 2 weeks. The steroid response can be confirmed on clinical images (computed tomography, ultrasonography, endoscopic ultrasonography, magnetic resonance imaging, and 18F-fluorodeoxyglucose-positron emission tomography). Hence, the steroid response is included as an optional diagnostic item of AIP. Steroid treatment results in normalization of serological markers, including IgG4. Short- and long-term corticosteroid treatment may induce adverse events, including chronic glycometabolism, obesity, an immunocompromised status against infection, cataracts, glaucoma, osteoporosis, and myopathy. AIP is common in old age and is often associated with diabetes mellitus (33-78%). Thus, there is an argument for corticosteroid therapy in diabetes patients with no symptoms. With low-dose steroid treatment or treatment withdrawal, there is a high incidence of AIP recurrence (24-52%). Therefore, there is a need for long-term steroid maintenance therapy and/or steroid-sparing agents (immunomodulators and rituximab). Corticosteroids play a critical role in the diagnosis and treatment of AIP.