A 38-year-old woman with a 22-year history of type 1 insulin-dependent diabetes presented with a complaint of a lump in the left breast. Physical examination revealed a palpable nodule in the left breast at the 2 o'clock periareolar region.
Prepared by J. Andrew Keyoung, MD, Department of Radiology,
Stanford University Medical Center, Stanford, CA; Rebecca A.
Zuurbier, MD, and Erini Makariou, MD, Betty Lou Ourisman Breast
Health Center, Department of Radiology, Georgetown University
Hospital, Washington, DC; Theodore N. Tsangaris, MD, Department
of Surgical Oncology, The Johns Hopkins Hospital, Johns Hopkins
Breast Center, Baltimore, MD; and Norio Azumi, MD, Department of
Pathology, Georgetown University Hospital, Washington, DC.
CASE SUMMARY
A 38-year-old woman with a 22-year history of type 1
insulin-dependent diabetes presented with a complaint of a lump in
the left breast. Physical examination revealed a palpable nodule in
the left breast at the 2 o'clock periareolar region. Diagnostic
mammography was performed (Figure 1). Directed ultrasound was then
performed (Figure 2). Based upon these findings, the patient
underwent ultrasound-guided core breast biopsy (Figure 3).
DIAGNOSIS
Diabetic mastopathy
IMAGING FINDINGS
Diagnostic mammography revealed a heterogenous dense (75% to 80%
fibroglandular tissue) breast parenchyma pattern in the left breast
without suspicious microcalcifications, masses, or architectural
distortions (Figure 1). The directed ultrasound examination at the
site of the palpable lump revealed a hypoechoic abnormality with
fingerlike projections and intense posterior acoustic shadowing.
The lesion measured 4 * 2 * 2 cm. (Figure 2).
PATHOLOGIC FINDINGS
Histologic evaluation revealed a dense stromal fibrosis and some
periductal lymphocytic infiltration without any evidence of atypia
or malignancy comparable with diabetic mastopathy (Figure 3).
DISCUSSION
Diabetic mastopathy is a benign process found predominantly in
patients with type 1 diabetes. These lesions are mainly composed of
primarily fibrotic and inflammatory elements. For this reason,
terms such as diabetic fibrous breast disease, diabetic fibrous
mastopathy, lymphocytic mastitis, and lymphocytic mastopathy have
also been used since its first description in 1984 by Soler and
Khardori.
1
The prevalence of diabetic mastopathy has been found to be
<1% of benign breast diseases, but prevalence can range from
0.6% to 13% in type 1 diabetics.
1-3
However, this clinical condition is infrequently encountered since
breast examination is not performed routinely in younger diabetic
patients. Diabetic mastopathy has been reported in women between
the ages of 32.2 and 62 years.
4
However, it is also known to occur in men with long-standing
diabetes.
5
The clinical criteria for diagnosis of diabetic mastopathy
includes a long-term (usually >5 years) history of type 1
insulin-dependent diabetes mellitus. The physical examination on
presentation is that of hard, irregular, easily movable, discrete,
painless breast masses. It can be solitary or multiple, and
unilateral or bilateral.
2
A patient can also have nonpalpable lesion.
6
These patients have been described to have dense fibroglandular
tissue at mammography. There have been no reported cases of
diabetic mastopathy consisting primarily of adipose tissue or mixed
fatty and glandular tissue. Strong acoustical shadowing behind the
palpable masses can be seen on sonography.
2
Attenuation increases due to the fibrotic nature of the masses.
Diabetic mastopathy may mimic malignancy ultrasonographically and
may have no significant mammographic manifestation, however.
Radiographic and morphologic differential diagnosis for diabetic
mastopathy includes invasive lobular carcinoma, simple fibrosis of
the breast, fibroadenomas with marked fibrosis, mammary
fibromatosis, leiomyomatas, and desmoid tumor.
7
Histologically, diabetic mastopathy lesions are composed of
dense stromal keloid-like fibrosis containing little or no adipose
tissue or cellular material. Furthermore, focal perivascular,
periductal, and/or perilobular lymphocytic infiltrations with
mature B-cell predominance are commonly seen. Epitheloid
fibroblasts in the interlobular stroma are also commonly observed.
3,8
The pathogenesis of diabetic mastopathy is unknown. Some have
postulated that since the currently accepted pathogenesis of type 1
diabetes is of autoimmune etiology, it is likely that diabetic
mastopathy is also due to an autoimmune process.
2,8
Nonenzymatic glycosylation of proteins can lead to metabolic and
functional abnormalities with neoantigen, resulting in the
autoimmune response. Since fibrous tissue deposition and collagen
pro-liferation in the breast are similar to that of other diabetic
complications, it is not unlikely that some patients with diabetic
mastopathy will have thyroid, eye, and joint involvement due to
their long-standing insulin-dependent diabetes.
Diabetic mastopathy has also been described in patients with
type 2 diabetes mellitus who had been exposed to exogenous insulin.
8
This suggests that the exogenous insulin may be related to its
development. This may be due to inflammatory or immunologic
reaction to the insulin, the vehicle, or a contaminant in the
vehicle.
There have been no reported cases of malignancy arising from
diabetic mastopathy to date; there has been one reported case of
regression.
7
In patients with recurrence, it tends to be in the same location
involving more breast tissue than previously seen.
7
CONCLUSION
Diabetic mastopathy should be considered in the differential
diagnosis of a diabetic patient under-
going a breast biopsy for ultrasonographic findings worrisome for
malignancy given the hypoechoic lobulated appearance with
finger-like projections. It should also be considered concordant at
radiographic-pathologic correlation.