Lesions of AGMLG present as a spectra of morphologic changes synonymous with those in the breast, including lactating adenoma, hidradenoma papilliferum, syringoadenoma papilliferum, fibroadenoma, phyllodes tumor, pseudoangiomatous stromal hyperplasia, extramammary Paget’s disease and other malignancies arising from AGMLG [6
]. Benign changes, such as apocrine, oxyphilic or squamous metaplasia, myoepithelial hyperplasia or clear cell metaplasia, lactation-like change and florid epithelial hyperplasia, have also occasionally been identified [6
]. To date, fibroepithelial lesions of AGMLG have only been reported in 44 female cases. As far as we know, there has been no report of a case of this tumor of AGMLG in a male patient.
We performed differential diagnoses to exclude possible hidradenoma papilliferum of skin appendage, phyllodes tumor of ectopic prostatic tissue, and tumors of AGMLG which are analogous with the breast neoplasm. Hidradenoma papilliferum can also be found in the anal region [7
]. However, hidradenoma papilliferum has a more complex papillary structure than the leaf-like pattern of benign phyllodes tumors [10
]. In hidradenoma papilliferum, glandular secretion is incapacitated. Because lesions of mammary glands and sweat glands stain for ER and GCDFP-15, immunohistochemistry may not be used to distinguish hidradenoma papilliferum from mammary lesions [8
]. Phyllodes tumor has been found in ectopic prostate tissue, mostly in female patients, the most common locations being the vulva, vagina, cervix, urinary bladder and anal canal [11
]. Gynecomastoid hyperplasia around the main lesion may cause a pathologist to suspect residual normal prostate glands. Mammary glands may show weakly positive for PSA. However, a positive finding of CK7 and negative finding for PSAP may help exclude the possibility of a prostatic origin (Figure
]. There are other tumors homologous to the breast tumor. One, periductal stromal sarcoma, also has a biphasic growth pattern. However, it does not have the leaf-like appearance of intracanicular growth pattern but rather a solid growth appearance of a pericanalicular pattern [14
]. Another such tumor is spindle cell carcinoma. The epithelioid nests of this tumor may merge with spindle stromal elements. Cytokeratin stain can help visualize these tumor cells clearly (Figure
]. Still another such tumor is fibroadenoma phyllodes, which is a histological feature similar to that of low-grade phyllodes tumor [15
]. It can be difficult to distinguish the two because there is a continuum of morphologic findings. However, if the lesion has well-formed leaf-like slits and the hypocellular stroma appears to the degree that is found in fibroadenoma, it is called fibroadenoma phyllodes [15
]. In our case, there was increased stromal cellularity and cell atypia. The proliferative index of stromal cells was found to be increased when viewing the Ki-67 Immunostain (Figure
f). Together, these characteristics help distinguish phyllodes tumor from fibroadenoma phyllodes. Regardless, in the mammary gland, both fibroadenoma and phyllodes tumor carry risk of local recurrence.
Benign lesions in AGMLG outnumber malignant ones more than they do in the breast, possibly because the anus has more superficial locations [6
]. In all patients reported previously, there was no recurrence of the tumor after excision [6
]. As of twenty months follow-up, no local recurrence was found in our case. It is unclear whether phyllodes tumor of AGMLG has a better prognosis than phyllodes tumor of the mammary gland. Because it is difficult to predict behavior of this tumor in mammary glands, the possibility of recurrence locally cannot be totally excluded. Likewise, it would be prudent to closely follow-up phyllodes tumor of AGMLG post-surgery.
According to Sandra J. , there is always concurrent gynecomastia in fibroadenoma of breast in men [5
]. Both gynecomastia and male breast cancer share hormonal imbalance as a same factor. Exogenous estrogen use in the male patient is evident [5
]. Because our case had gynecomastoid hyperplasia and tumor on his AGMLG, we were concerned that he may also have a hormone imbalance as well as gynecomastia or tumor on the breast. However, his hormone levels (prolactin, beta-hCG, testosterone, E2, LH, FSH, T3, T4) were within normal range, and no gynecomastia or tumor was found in breast. These negative findings could be interpreted to suggest that our patient’s phyllodes tumor and gynecomastoid hyperplasia of AGMLG resulted from localized hormone change. Although we found no peripheral hormone change, it might be still wise to monitor hormone levels in other such patients because of the known strong association between hormone level and gynecomastia as well as male breast cancer.
The alterations in ratio of androgen to estrogen may be influenced by many factors [16
]. In middle-aged men, changes in this ratio can be caused by testicular or adrenal tumors, hormone-secreting tumors, hormone deficiency, prostate cancer, obesity, liver or renal disease, medical history of disease or drug abuse. Our male patient had normal hormone status (prolactin, beta-hCG, testosterone, E2, LH, FSH, T3, T4), and denied taking any drugs except for those he was taking for hypertension and depression. However, in such patients, it is necessary to take a careful medical and drug-use history as well as perform comprehensive evaluations, including physical examination, imaging, and laboratory evaluations.