Mucinous adenocarcinoma of testis-a rare case report.
Microscopy: Histopathological examination of H&E stained section showed tissue composed of single layer of columnar epithelium with focal areas of stratification arranged in pseudopapillary pattern and stromal invasion. Also seen are pools of mucin in the fibromyxoid stroma replacing the normal testicular parenchyma. [Image 1, 2] Individual cells are cuboidal to columnar exhibiting marked pleomorphism and with hyperchromatic nucleus [Image 3].No teratomatous elements and germ cell neoplasia was evident. Also sections from rete testis and epididymis were normal and free from tumor invasion.
DISCUSSION: Primary ovarian-type surface epithelial carcinomas of the Testis and Para testis are rare. Six subtypes have been defined: a) Serous b) Mucinous c) Endometrioid d) Clear e) Transitional & f) Squamous. The most frequent of these is the serous subtype; while the mucinous subtype is very rare . The incidence of these tumours is higher among older age groups, with a median age at onset of 54 years. (2,3) Similar to ovarian tumours, the biological behaviour ranges from benign to borderline to malignant with metastasis. Although the gross features resemble the well-known ovarian tumours, a few differences are worth noting. Testicular tumours are not generally as large as the ovarian ones, and the more conspicuous location results in patients seeking attention earlier. As a result, the chief complaint is commonly painless enlargement of the testis, sometimes with a hydrocele and rarely with infertility. Compared to an ovarian tumor, a testicular tumor is more often a unilocular cystic tumour. The histogenesis of the ovarian-type surface epithelial tumours of the testis and paratestis remains unclear. These tumours are possibly derived from mullerian remnants or by metaplasia of the mesothelium of the tunica vaginalis. The most important differential diagnosis is metastasis from the gastrointestinal tract. In cases with ovarian tumours, immunostaining for cytokeratin 7, MUC2, MUC5AC, and MUC6 has been reported to be useful in distinguishing from metastatic tumors.  Also, with intratesticular mucinous adenocarcinoma, some reports have suggested the utility of immunohistochemical staining. However, solid evidence is lacking, because of unavailable material and lack of specific markers. The possibility of metastatic lesions from other primary sites should thus be excluded by appropriate clinical, endoscopic, and radiographic investigations. The standard treatment for localized disease is radical orchidectomy. The significance of adjuvant chemotherapy remains controversial, as most reported cases have not shown metastases and had a good prognosis but some cases showed metastatic spread.
Mucinous neoplasms of testis both benign and malignant have only sporadic representation in literature. Kellert described the first case in 1959; that involved an ovarian-type pseudomucinous cystadenoma in the scrotum. He attributed the origins of the tumour to persistent mullerian duct remnants.  Young and Scully described 4 cases of testicular and paratesticular tumors. They discussed these tumors in terms of the mullerian-type epithelium that occurs in the vicinity of the testis and epididymis.  Nistal et al described a case of bilateral mucinous cystadenocarcinoma of the testis and epididymis. They suggested a mesothelial origin citing tubular connections between the mesothelium covering the tunica albuginea and seminiferous tubules, which are implicated in testicular disorders, as well as in the normal testis. However, they also cited that their case may have originated directly in the mullerian remnants.  Likewise, Elbadawi et al reported a case of intratesticular papillary mucinous cystadenocarcinoma in a 60-year-old man, citing mullerian remnants as the likely culprit in its histogenesis.  Recently, Mesia et al described a case of ossified intratesticular mucinous tumour of low malignant potential. Because rare foci of mature bone were found in the cyst wall, a teratoma could not be ruled out. Most of the bone identified in this case was located in fibrotic areas, supporting the presence of metaplastic change similar to the ovarian counterpart. The article didn't conclude the etiology of the tumor. 
The most recent series by Ulbright and Young nine cases of primary mucinous tumors of the testis and paratestis were described. Two cases from this series described as mucinous cystadenoma were both paratesticular, unlike the intratesticular cases described herein. They are also characterized by testicular counterparts to ovarian mucinous tumors, for which the histologic findings could represent a form of neometaplasia of the epithelium, rather than supporting a germ cell origin. 
CONCLUSION: The mucinous adenocarcinoma of testis behaves similar to that of its ovarian counterparts. Standard treatment is radical orchidectomy while adjuvant chemotherapy might have potential efficacy. [9,10] Clinical evaluation is necessary to rule out metastatic spread from a primary adenocarcinoma of the appendix, colon, stomach, pancreas, lung, or prostate. A literature review reveals an extensive controversy regarding the origins of these rare tumors, mostly surrounding mullerian versus mesothelial and germ cell derivations. While our study does not resolve this controversy, we believe that the microscopic, clinical and radiographic evidence classifies this tumor as a testicular mucinous adenocarcinoma.
[1.] D. Henley, J. Ferry, and T. M. Ulbright, "Miscellaneous rare paratesticular tumours," Seminars in Diagnostic Pathology, vol. 17, no. 4, pp. 319-339, 2000.
[2.] M.Nokubi, T.Kawai, S.Mitsu, S.Ishikawa and S.Morinaga, "Mucinous cystadenoma of the testis," Pathology International, vol. 52, no. 10, pp. 648-652, 2002.
[3.] Young RH, Scully RE. Testicular and paratesticular tumours and tumour-like lesions of ovarian common epithelial and mullerian types: a report of 4 cases and review of the literature. Am J Clin Pathol. 1986; 86:146-152
[4.] Kellert E. An ovarian type pseudomucinous cystadenoma in the scrotum. 1959; 12: 187-190.
[5.] Nistal M, Revestido R, Paniagua R. Bilateral mucinous cystadenocarcinoma of the testis and epididymis. Arch Pathol Lab Med. 1992; 116: 1360-1363
[6.] Elbadawi A, Batchavarov MM, Linke CA. Intratesticular papillary mucinous cystadenocarcinoma. Urology. 1979; 14: 280-284.
[7.] Mesia L, Georgsson S, Zuretti A. Ossified intratesticular mucinous tumour. Arch Pathol Lab Med. 1999; 123: 244-246.
[8.] T.M.Ulbright and R. H. Young, "Primary mucinous tumors of the testis and paratestis: a report of nine cases," American Journal of Surgical Pathology, vol. 27, no. 9, pp. 1221-1228, 2003.
[9.] M.Shimbo, K. Araki, T.Kaibuchi, H.Kuramochi, and I.Mori, "Mucinous cystadenoma of the testis," Journal of Urology, vol. 172, no. 1, pp. 146-147, 2004.
[10.] D.J.Vaughn, T.A.Rizzo and S.B.Malkowicz, "Chemo sensitivity of malignant ovarian-type surface epithelial tumour of testis," Urology, vol. 66, no. 3, pp. 658.e7-658.e9, 2005.
N. Bharat Rao (1), G. Sudhakar (2), V. Ramya Swathi (3), A. Hareesh Kumar (4)
(1.) N. Bharat Rao
(2.) G. Sudhakar
(3.) V. Ramya Swathi
(4.) A. Hareesh Kumar
PARTICULARS OF CONTRIBUTORS:
(1.) Professor, Department of Pathology, Siddhartha Medical College, Vijayawada.
(2.) Associate Professor, Department of Pathology, Government medical college, Anantapur.
(3.) Post Graduate, Department of Pathology, Siddhartha Medical College.
(4.) Post Graduate, Department of Pathology, Siddhartha Medical College.
FINANCIAL OR OTHER COMPETING INTERESTS: None
NAME ADDRESS EMAIL ID OF THE CORRESPONDING AUTHOR:
Dr. N. Bharat Rao, # 16-3-33A, Kowthasubbarao Street, Poornanadam Pet, Vijayawada.
Date of Submission: 26/08/2015.
Date of Peer Review: 27/08/2015.
Date of Acceptance: 11/09/2015.
Date of Publishing: 15/09/2015.
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|Title Annotation:||CASE REPORT|
|Author:||Rao, N. Bharat; Sudhakar, G.; Swathi, V. Ramya; Kumar, A. Hareesh|
|Publication:||Journal of Evolution of Medical and Dental Sciences|
|Date:||Sep 17, 2015|
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