Idiopathic Granulomatous Mastitis

  • Idiopathic granulomatous mastitis (IGM):
    • Is a rare benign inflammatory breast disease first described in 1972 by Kessler and Wolloch
  • The most common presenting symptom is:
    • A unilateral, firm, and discrete breast mass:
      • Which may be accompanied by overlying skin changes and / or possible lymph node involvement with idiopathic granulomatous mastitis
      • The average duration of symptoms is around 3.9 months with:
        • The most common signs and symptoms including discrete mass, tenderness to palpation, erythema, and swelling
        • The pain could be out of proportion to findings:
          • Suggestive of a localized ischemic etiology
        • The pain could be a motivating factor in prompting all symptomatic patients to seek consultation
    • The lesion may occur in any quadrant of the breast:
      • But often extends radially from the retroareolar region
  • The disease often presents in women:
    • Of childbearing age with a recent history of pregnancy or ongoing lactation:
      • The mean age of diagnosis is around 31.7 years and all within reproductive years
      • The high majority of women are Hispanic or African / African-American ancestry
      • A history of previous granulomatous disease (tuberculosis, sarcoidosis, autoimmune disease, or granulomatous disease) is very rare
  • The overlap of presenting symptoms with other disease processes such as:
    • Malignancy, acute or chronic infections, and chronic inflammatory diseases:
      • Makes definitive diagnosis difficult
  • Because the differential may include malignancy:
    • The patient may experience significant anxiety during the evaluation
  • In addition, the broad differential and the lack of pathognomonic features make definitive diagnosis difficult:
    • Often resting as a diagnosis of exclusion on a clinical basis
  • The typical mammographic and ultrasonographic findings of granulomatous mastitis are:
    • Mammogram:
      • Ill-defined mass to an asymmetric density without specific margins
      • It is usually not accompanied by microcalcifications or architectural distortion
  • Ultrasound:
    • Heterogeneously hypoechoic lesion
    • Segmental masses with ill-defined margins, with tubular structures extending from the mass:
      • The tubular structures may be clustered, separate or contiguous
  • Malignant features or findings:
    • Suspicious microcalcifications, architectural distortion, or intra-ductal mass:
      • Would warrant appropriate histologic diagnosis and subsequent management
  • If the findings clinically and radiographically indicate an abscess:
    • They warrant treatment with antibiotics along with drainage by aspiration or incision, if the abscess is larger
  • Idiopathic granulomatous mastitis is usually regarded as a sterile process:
    • However, there is evidence to suggest a link to Corynebacterium kroppenstedtii infection or colonization:
      • This would then mandate routine cultures
    • One-third of the patients with granulomatous mastitis who are evaluated:
      • Have findings suggestive of an abscess
  • Because diagnosis is difficult, patients typically have received:
    • Prolonged courses of antibiotics, frequent biopsies, or surgical procedures
  • With a lack of pathognomonic imaging findings associated with granulomatous mastitis:
    • Histopathology is key to confirming a diagnosis
  • Histologically:
    • The disease has been described as non-caseating granulomas among epithelioid histiocytes and multinucleated giant cells surrounded by lymphocytes and plasma cells
    • Histologic differentials begin with the use of:
      • Hematoxylin and eosin stains, gram stain, and may also include acid fast stains and Grocott’s methenamine silver to evaluate for the possibility of sarcoidosis or mycobacterium infection
  • Once the diagnosis is made, treatment strategies are not clearly delineated but are often supportive
  • Steroid treatment has been shown to decrease the extent of involvement, and enable complete resection with removal of less breast tissue should resection be pursued
    • However, lower doses have also proven to be efficacious and help to avoid adverse effects of weight gain, hyperglycemia, and Cushingoid symptoms
    • Regimens of 16 mg of prednisone twice a day for two weeks with a slow taper over a two-month period are described in the literature, as is prednisolone 30 mg/day for eight weeks, with taper
  • If symptoms do not improve, a course of methotrexate could be utilized:
    • Since there is a contingent who feel that this disease is an abnormal immune response
    • Success with methotrexate, including administration in steroid refractory cases:
      • Is limited to small studies of 3 to 5 patients
    • In consideration of the duration of symptoms patients experienced, along with the lack of durable evidence favoring treatment with methotrexate, our institution favors proceeding directly to surgery in steroid-refractory cases
  • We recommend the surgical options of:
    • Wide local excision for focal involvement and
    • Total mastectomy with the option of reconstruction for diffuse involvement
    • A 15% to 20% recurrence rate has been reported for surgery alone:
      • And inversely proportional to negative surgical margins
    • In light of the fact that these masses are painful and may lead to fistula formation and deformity:
      • Intervention may be the preferred path to avoid progression or static disease
      • Our experience allowed for a trial of “conservative” medical management for two months:
        • Followed by treatment escalation for lack of progress
  • A course of methotrexate may be entertained in patients who desire continued attempts at medical management, to help preserve breast tissue
    • However, it is not included in the first line of conservative management

#Arrangoiz #BreastSurgeon #BreastCancer #IGM #IdiopathicGranulamatousMastitis #CASO #Miami #CenterforAdvancedSurgicalOncology #CancerSurgeon

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