Idiopathic Granulomatous Mastitis: Cytologic and Histologic Study of 65 Egyptian Patients

Abstract

Background: The etiology of idiopathic granulomatous mastitis (IGM) is unknown, and it is commonly misdiagnosed clinically and/or radiologically as breast cancer. The role of fine-needle aspiration cytology (FNAC) in its diagnosis is still a matter of debate. The aim of the current study is to assess the value of FNAC in the diagnosis of IGM, and to search for the presence of bacteria in IGM with cystic vacuoles, which was described recently by a few authors. Materials and Methods: Retrospective study of cytologic smears and histologic tissue sections of 65 Egyptian IGM cases was done along with microbiologic testing. A comparison of the frequency of IGM in Egypt to that of other populations was also made. Results: IGM has typical FNA features which can easily exclude malignancy. Histologically, cystic vacuoles were encountered in 35 out of 65 cases (53.9%), with only 6 (17.14%) of these cases showing Gram-positive bacilli (GPB). The frequency of IGM in Egypt is comparable to those in other Middle Eastern countries but much higher than in Western countries. Conclusion: IGM is a common breast disease in Egypt. FNAC in IGM has a high diagnostic accuracy. This study supports the few recent studies that have detected GPB in IGM with cystic vacuoles. Thus, bacteriologic examination in such cases may affect the treatment strategy.

Cytomorphological features of cystic neutrophilic granulomatous mastitis on ThinPrep

“…The cytological criteria for diagnosing GM are not well defined. Several reports on GM describe a predominantly neutrophilic infiltrate with aggregates of epithelioid histiocytes, multinucleated giant cells, lymphocytes, and plasma cells, which lack necrosis . In comparison, tuberculous mastitis, the main differential diagnosis, shows epithelioid granulomas with or without caseating necrosis.…”

“…Several reports on GM describe a predominantly neutrophilic infiltrate with aggregates of epithelioid histiocytes, multinucleated giant cells, lymphocytes, and plasma cells, which lack necrosis. 8,14,15 In comparison, tuberculous mastitis, the main differential diagnosis, shows epithelioid granulomas with or without caseating necrosis. In certain cases, it may be challenging to distinguish the atypical, mononuclear, epithelioid histiocytes seen in GM from the neoplastic cells of epithelial mammary origin, and in these circumstances, the inflammatory background and close attention to the cytological features of histiocytes can aid in the diagnosis of GM.…”

Clinical and Cytological Spectrum of Granulomatous Mastitis and Utility of FNAC in Picking up Tubercular Mastitis: An Eight-Year Study

“…Cytology of the NGM is characterised by presence of non-caseating epithelioid granulomas, multinucleated giant cells with or without necrosis [18]. These findings overlap with that of TBM.…”

“…Our study is the first one to record the consistent presence of plump histiocytes in TBM. Multinucleated giant cells are common in granulomatous mastitis [17,18]. They were mostly foreign body type, seen in 75% NGM smears and Langhans giant cells seen in 60% of TBM smears.…”

Mastitis in Autoimmune Diseases: Review of the Literature, Diagnostic Pathway, and Pathophysiological Key Players

“…Indeed, Helal and coll. report 17% (6/65) of IdGM in Egyptian patients showing Gram-positive bacilli in their breast biopsies [146]. A prospective study suggests that treatment with rifampicine for 6-9 months led to a complete remission of IdGM in 30 patients after a 15-month follow-up [147].…”