Discussion:
GM is diagnosed histologically by confirming the presence of
non-necrotizing granuloma formation, without any evidence of
microorganisms such as Mycobacterium or fungi.2 Its
etiology is uncertain, and imaging findings are not specific. GM occurs
in female breasts and accounts for 1.8% of benign breast disorders
proven by biopsy.3 It mainly affects females of
reproductive age. The mean age at presentation is 33–38
years.1,4,5 Hormonal disruption and autoimmune
responses have been suggested as the possible etiological
factors.6
GM is rarely observed in males. To the best of our knowledge, there are
only 16 reported cases of GM in male patients.1,2,4-15The reported cases have been summarized in Table 1. We analyzed 12 cases
of patients whose characteristics and clinical courses were
described.2,6-15 The median age of the patients at the
time of presentation was 46 years (range: 17–60 years). Eight patients
(73%) had GM in the right breast, while two (17%) presented with
bilateral involvement. The median size of the masses was 20 mm (range:
5–72 mm). All patients had a breast mass with or without pain, while
two (17%) had ulcerations. Nipple discharge was observed in only one
patient (8%). A definitive diagnosis of GM was obtained by core needle
biopsy in eight patients (67%), by fine needle aspiration in one
patient (8%), and by excisional biopsy in three patients (25%). The
baseline characteristics of female GM patients have been described as
follows: mean age of 36 years, lesion measuring approximately 50 mm, and
nipple discharge observed in 30% patients.16
One possible reason for rarity in males is the absence of mammary
lobules, which are usually affected during this disease. It has been
reported that estrogen stimulation causes the development of acini and
lobules in male breasts2 and might be responsible for
the development of GM. Of the 12 cases, four patients had
gynecomastia10,14,15,16 and one was a transgender
(male to female transition, receiving estrogen therapy for six
years).2 This supports the fact that GM in males might
be associated with abnormal hormonal conditions such as gynecomastia and
estrogen therapy. This may also be responsible for the higher age of
affected male patients compared to female patients, since the ratio of
androgen to estrogen in males lowers with age.18However, hormonal involvement was not detected in the remaining seven
cases and our case. Therefore, it can be concluded that the etiology of
GM in males remains unclear.
The optimal treatment strategy for GM remains controversial. Treatment
approaches include observation, oral corticosteroid administration, and
surgical excision. Incision and drainage may be a treatment option for
bacterial infection cases. Oral corticosteroids have been used as the
first-line treatment in some studies and reported to be effective in
decreasing the size of GM.4 However, observation
without any therapeutic intervention could be considered for
asymptomatic cases. Some studies have reported that GM patients who
underwent observation without any medication achieved resolution in
7–14.5 months.19,20
Of the 11 reported male cases in which treatment was mentioned, four
patients underwent surgical excision. Core needle biopsy was not
attempted in these four cases, and the lesion was surgically excised in
toto as an excisional biopsy. Of the remaining seven patients, four who
received oral corticosteroid therapy were symptomatic, whereas two who
underwent observation did not have any symptoms other than the breast
mass. In one patient who was treated with bromocriptine for pituitary
tumor, the breast tumor disappeared after the treatment. None of the
patients experienced recurrence during their clinical course, but the
follow-up periods were not sufficient to determine the long-term
outcomes. In our case, since the patient was asymptomatic and diagnosis
of GM was confirmed histologically, we decided to observe the lesion.
In contrast to other reported cases, the tumor in our case appeared
during the clinical course of follicular lymphoma treatment. Although
not histologically proven, one possible explanation for the occurrence
of GM in our case may be the autoimmune response toward the extranodal
lesion of lymphoma in the breast.
To summarize, we presented a rare case of GM in a male patient.
Observation may be a viable option in the asymptomatic cases. However,
further studies including a larger number of patients and longer
observation period are needed for reliable long-term outcomes.