Ali Kemal UZUNLAR(1), Mehmet YALDIZ(1), Enver OZDEMIR(2), Fahri YILMAZ(1) and Mehmet OZAYDIN(1)

1) Department of Pathology, Dicle University, Faculty of Medicine, Diyarbak, Turkey
2) Department of Urology, Dicle University, Faculty of Medicine, Diyarbak, Turkey

Corresponding Address:
Ali Kemal UZUNLAR, M.D.
Dicle Universitesi, Tip Fakultesi,
Patoloji ABD.
21280 Diyarbak, TURKEY
Tel: +90 412 488155
Fax: +90 412 2488440

Adenomatoid tumors are regarded as uncommon neoplasms of the paratesticular tissues, probably of mesothelial origin. We report a case of adenomatoid tumor accompanying with seminoma and review the relevant literature. Ours is the first documented adenomatoid tumor accompanying with seminoma in the available literature. Because of its rarity, the clinical and histopathological aspects are discussed.
Key Words: Adenomatoid tumor; paratesticular; seminoma

Adenomatoid tumors were first described in 1945 by Golden and Ash (1). They are rare benign tumors that primarily occur in the paratesticular tissues such as; epididymis, spermatic cord, testicular tunica and ejaculatory ducts (2), and quite a few were reported in the intratesticular, prostate and suprarenal areas (3,4,5,6,7,8).
Adenomatoid tumors occur over a wide-range of age, from adolescence to the elderly (9). They are well-recognized neoplasms generally considered to be of mesothelial origin (10). The tumor is usually a well-circumscribed, firm, white to tan nodule and as a rule its diameter ranges from 1 to 2 cm (11,12).
We describe here a case of adenomatoid tumor accompanying with seminoma in our department and review the relevant literature.

A 39-year-old man presented with scrotal enlargement to outpatient department of our Hospital, Dicle University Hospital. His chief complaint was pain on the right testis. He had no history of testicular trauma and orchitis. Physical examination revealed a mass in the right testis. Fine-needle aspiration was not performed. On the scrotal ultrasound examination there was a 3-cm round solid mass in the lower pole of the right testis together with a well defined 0.9 cm solid lesion lying on the border between epididymal tail and lower pole of the right testis. The echogenicity of the big mass was hipoechoic and that of small mass was isoechoic. Preoperative laboratory test results, including a chemistry panel, alpha-fetoprotein beta-HCG, FSH, LH, estradiol, prolactin, testosterone were within normal limits. Serum LDH level was the only elevated marker, 600 U/L (60-125 U/L). The clinical impression was a probable germ cell neoplasm. There was no clinical or radiographic evidence of metastatic disease. The patient subsequently underwent a total right orchiectomy. Macroscopically, the cut surface of the right testis, measured 8 x 5 cm, contained a light tan, lobulated mass, measured 3 x 2 cm in dimension in the lower pole and there was another well circumscribed white-grayish nodule without encapsulation, measured 0.9 cm in diameter in the lower pole. The small mass was in direct contact with the tail of the epididymis and the bigger mass.
On microscopic examination, cells of the big mass characteristically had clear to lightly eosinophilic cytoplasm and central nuclei, often with slightly squared edges, and one or two large central nucleoli. The cells had well-defined cytoplasmic borders. There were lymphocytic infiltrates in and around the fibrous trabeculae (Fig. 1). This tumor was diagnosed as a classic seminoma.
The small mass, histologically, had tubules and cords of vacuolated cells. The cells lining the tubules varied from flattened to cuboidal, usually with a prominent intervening fibrous stroma. The cellular vacuoles had a signet ring-like appearance in some fields, but epithelial-type mucin was not present. Some tumor cells had abundant cytoplasm and the nuclei with small nucleoli. There was no mitotic activity (Fig. 2). Immunohistochemically, the absence of carcinoembryonic antigen and factor VIII antigen favoured adenomatoid tumor. This nodule was diagnosed as a adenomatoid tumor in the epididymis.
The final pathological diagnosis was adenomatoid tumor together with classic seminoma in the same testis (Fig. 3). The serum LDH value was returned to normal range at three month control examination. The follow-up examinations up to eleven months were normal.

Adenomatoid tumors account for approximately 30% of all paratesticular tumors (13) and most frequently seen in the epididymis, being located especially at its lower pole (13,14) and with equal frequency on both sides. Most of the adenomatoid tumors occur in third to fifth decades of life with a wide age range from adolescence to the elderly (9). They typically present as small firm asymptomatic intrascrotal masses, but there may be pain or tenderness (15). Adenomatoid tumors generally remains unchanged in size for years.
As a rule the diameter of the tumor ranges from 1 to 2 cm, the largest reported diameter being 12 cm (12). The structural growth pattern of adenomatoid tumors also is atypical of benign neoplasms, since they are generally not encapsulated, and tumor elements are not uncommonly present between structures of adjacent tissues and may show local infiltration (3). Follow-up shows that this invasive-like growth pattern does not indicate a malignant potential, since there have not been any reports of recurrent adenomatoid tumors in the literature (16). However, a malignant form of tumor also has been reported (17).
The adenomatoid tumor microscopically has characteristic appearance. One of the important characteristics is tubular structures composed of vacuolated cell (18). Some cellular vacuoles had a signet ring-like appearance. Mitotic cells are mostly absent (7). In addition to these figures, immunohistochemically, the absence of carcinoembryonic antigen and factor VIII antigen helps pathologist to diagnose the adenomatoid tumor (19). Our case had classic seminoma as a second tumor.
Although the possible histogenesis of adenomatoid tumors has aroused controversy and some data are contradictory, the most recent investigations favor a mesothelial origin (10,16,19). Chronic mesothelial irritation in association with ascites or a hernial sac is known to cause a hyperplastic reaction in the mesothelium or adenomatoid tumor. However, it is difficult to find such irritating factors in intrascrotal adenomatoid tumors (16).
Adenomatoid tumor can be confidently treated by local excision (19), but our patient underwent a total right orchiectomy and afterwards chemotherapy, because of having seminoma.
In conclusion, ours is the first report that an adenomatoid tumor seen in the same testis together with seminoma synchronously. Moreover, the presence of adenomatoid tumor accompanying with seminoma, in our patient, may be coincidental, or the effect of the seminoma on the mesothelial cells may be a factor for the development of adenomatoid tumor. However, there is no any available literature to explain this the possible histogenesis of adenomatoid tumor.

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Figure 1. Seminoma is formed by tumor nests separated by fibrous strands containing inflammatory cells (H&E, original magnification, X200).

Figure 2. Adenomatoid tumor showing tubules lined by flattened cells. The cellular vacuoles had a signet ring-like appearance in some tubules (H&E, original magnification, X300).

Figure 3. The adenomatoid tumor (right) and classic seminoma (left) (H&E, original magnification, X100).

Nagoya City University
Medical School