Adenomatoid tumor of epididymis: A rare case report and literature review :Chan-Jung Liu, Ho-Siang Huang, Urological Science

LETTER TO THE EDITOR
Year : 2018 | Volume : 29 | Issue : 3 | Page : 168--171

Adenomatoid tumor of epididymis: A rare case report and literature review

Chan-Jung Liu, Ho-Siang Huang
Department of Urology, National Cheng-Kung University Hospital, Tainan, Taiwan

Correspondence Address:
Chan-Jung Liu
No. 138, Sheng Li Road, Tainan
Taiwan

Abstract

Adenomatoid tumors are rare benign neoplasms in the scrotum that can occur in both sexes. The majority of the patients was asymptomatic and was incidentally found with scrotal mass. It is difficult to distinguish adenomatoid tumors from malignant intratesticular solid tumors, which may result in unnecessary orchiectomy. The present report describes a 64-year-old male presented with right testicular enlargement for 6 months. Radiological images and intra-operative findings all showed cystic mass attached to right testis. Right orchiectomy was performed and final pathology was adenomatoid tumor. The present report also summarizes the morphological and immunohistochemical features of adenomatoid tumors and reviews the literature to share this rare intrascrotal benign tumors.

How to cite this article:
Liu CJ, Huang HS. Adenomatoid tumor of epididymis: A rare case report and literature review.Urol Sci 2018;29:168-171

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Liu CJ, Huang HS. Adenomatoid tumor of epididymis: A rare case report and literature review. Urol Sci [serial online] 2018 [cited 2023 Sep 25 ];29:168-171
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Full Text

Introduction

Adenomatoid tumors are rare benign neoplasms that can occur in both sexes. These mostly originate from genital organs and are thought to arise from mesothelial cells. The majority of the patients was asymptomatic and was incidentally found with scrotal mass. Most of these tumors are small in size, with most <2 cm. Adenomatoid tumor accounted for 55% of epididymal tumors, followed by leiomyomas (11%) and by papillary cystadenomas (9%).[1] In most circumstances, gross examination of adenomatoid tumors shows a small, round, solid tumor of an elastic consistency. On section, a white, yellow, or brown surface of a fibrous appearance will be seen. Adenomatoid tumors with cystic appearance are very rare. To the best of our knowledge, fewer than 100 cases have been reported in the literature. Besides, to the best of my knowledge, no similar case had been reported in Taiwan. Since most intrascrotal masses are malignant tumors, we present this rare but benign intrascrotal tumor. It is imperative that all urologists should be aware of this rare disease to avoid unnecessary extensive surgical resection.

Case Report

A 64-year-old man presented to the urology department with progressive right testicular enlargement for 6 months. No associated testicular pain or fever was mentioned. His physical examination was unremarkable, except for a small nontender intratesticular intrascrotal mass at the middle pole of the right testis. Pelvic computed tomography revealed cystic mass with septum on testis superior portion in the right scrotum [Figure 1] and [Figure 2]. No obvious intratesticular mass was found. Serum tumor markers – including alpha-fetoprotein, beta-human chorionic gonadotropin, and lactate dehydrogenase – were all within normal limits. The patient subsequently underwent the right testicular exploratory surgery. During the surgery, one cystic mass protruded was firmly attached to the lateral superior side of the right testis [Figure 3] and [Figure 4]. The margin between testis and epididymis was not clear. Some fluid accumulated in the right testis, which suggested mild right hydrocele. The extratesticular cystic mass was completely removed. The final histology resection showed irregular dilated channels or tubules of varying sizes lined by a thin layer of cuboid cells [Figure 5]. The lining cells were positive for cytokeratin and negative for CD31 [Figure 6]. The results strongly suggested an adenomatoid tumor growing from the epididymis.{Figure 1}{Figure 2}{Figure 3}{Figure 4}{Figure 5}{Figure 6}

Discussion

Adenomatoid tumors account for nearly 30% of all paratesticular tumors and are the most common type of paratesticular benign tumors. Following adenomatoid tumor (73%), papillary cystadenoma (11%), and leiomyoma (9%) are also common benign tumors of epididymis.[1] Adenomatoid tumors were first reported in 1945 by Golden and Ash.[2] Adenomatoid tumors have mostly been reported in the head of the epididymis. The spermatic cord, prostate, and ejaculatory ducts are also reported as affected sites.[3],[4],[5] Adenomatoid tumors are rarely involved in the testicular parenchyma and present as intratesticular masses.[4],[6] In females, the uterus, fallopian tube, and ovary can all be affected.[7] Other than the genital organs mentioned above, adenomatoid tumors have also been found in the adrenal gland.[8]

The histological origins of adenomatoid tumors were believed to be of mesothelial, Müllerian, mesonephric, and endothelial origin. Among all, the mesothelial origin is the most acceptable theory. Delahunt et al. reported 12 cases of paratesticular adenomatoid tumors and investigated the histogenesis of paratesticular adenomatoid tumors using immunohistochemical markers for a variety of carcinomas and mesothelioma.[9] The immunohistochemical results of paratesticular adenomatoid tumors strongly support a mesothelial cell origin.

Most patients of adenomatoid tumors tend to be 30–50 years old, but neoplasm has been reported in patients aged from 18 to 80 years.[10] Most patients incidentally present hard intrascrotal masses, where the majority of intrascrotal mass grew very slowly and persisted asymptomatically. Very few epididymal adenomatoid tumors are accompanied by pain.

Ultrasonography is the method of choice for diagnosing scrotal pathology preoperatively. The sonographic appearance of adenomatoid tumors of epididymis has been variably reported. In most cases, they are found with hyperechoic and homogeneous characteristics.[11],[12] However, Feuer et al. reported three cases of adenomatoid tumor, and two of these were described as isoechoic intratesticular intrascrotal lesions.[13] Ultrasonography sometimes does not offer enough information to differentiate, and magnetic resonance imaging (MRI) is important for establishing the diagnosis before surgery. Watanabe et al. have shown that dynamic contrast-enhanced MRI is useful in distinguishing testicular tumors from other testicular abnormalities.[14] Malignant testicular tumors have increased contrast enhancement rather than contralateral normal enhancement of testicular parenchyma. Interestingly, Patel and Silva reported a local MRI finding of adenomatoid tumors, which highlighted the hyperenhancement of the tunica compared to the adenomatoid tumor and testicular parenchyma.[15] The real cause of this MRI finding is still unknown.

Macroscopically, adenomatoid tumors are usually firm, smooth, round, single, gray-white or yellow, and usually <2 cm in size. Microscopically, the tumor is characterized by a series of variable irregular spaces coated by a layer of flat or cubic epithelial cells surrounded by collagenous stroma, or even muscle fibers. A typical feature is the presence of vacuoles inside epithelial cells. Vacuoles can be tiny or large and sometimes will gradually occupy most of the cell cytoplasm. Another common presentation of these lesions is lymphoid aggregates, which are often localized at the periphery of the tumor.

The immunohistochemical profile of adenomatoid tumors is positive for pancytokeratins, podoplanin, WT1, and calretinin. Among these, calretinin has the most accurate sensitivity for identifying mesotheliomas and mesothelial cells, and its expression in malignant tumors is very rare. The immunohistochemical stains positive for adenomatoid tumors can also be very useful for differentiating other neoplasms that are easily confused with adenomatoid tumors, namely, yolk sac tumor (negative for WT1 and calretinin), Leydig cell tumor (negative for WT1), and metastatic carcinoma.[16] In addition, negative tests for epithelial markers, such as factors VIII or CD34, can exclude the tumors of vascular origin.

Adenomatoid tumors have never shown malignant behavior. No cases of malignization, metastasis, or relapse after removal have been reported. Treatment involves surgical removal, which aims to prevent unnecessary orchidectomy, thus preserving fertility and testosterone production. Enucleation or epididymectomy can all be considered while an intraoperative biopsy confirms its benign nature. However, in the literature, rare cases have been treated with conservative testicular-sparing surgery. This is due to the difficulty in clinical practice for a pathologist to rule out malignancy based on frozen sections, such as in cases of an adenomatoid tumor. Therefore, in general, orchiectomy is an acceptable management option for adenomatoid tumors. However, if there is no any suspicion of malignancy, the treatment of choice is total or partial epididymectomy, and radical orchiectomy should not be generally recommended as a first-line treatment.

Conclusion

Epididymal adenomatoid tumors are a relatively rare and benign tumor. Urologists should keep this less common diagnosis in mind before surgery. Intraoperative frozen sections can be considered if testicular tumor profiles or ultrasonography results all indicate that the tumor is not malignant. Orchiectomy should be avoided if the frozen section confirms that the tumor is benign.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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