Xanthogranulomatous Orchitis after Blunt Testicular Trauma Mimicking a Testicular Tumor: A case Report and Comparison with Published Cases INTRODUCTION Xanthogranulomatous inflammation is one form of chronic inflammation characterized by a cellular infiltrate of lipid-laden macrophages(1). It is considered to be mainly caused by ascending or hematogenous infection, however clear pathogenesis is still unknown(2). In the genitourinary system, xanthogranulomatous inflammation is commonly observed in kidney(3), bladder(4) and prostate(5). It can also occur in the gall bladder(6). Xanthogranulomatous orchitis (XGO) is a rare disease and, to our knowledge, only 22 cases have been reported to date. We present a case of XGO after blunt testicular trauma and compared with the published cases. CASE REPORT A 28-year-old man was hurt when his left testis was pinched in between the bicycle saddle and his left thigh. He had felt a dull pain in his left testis after the trauma, and a month later, he noted a lump in his left testis and visit- ed our department. There was no history of urinary tract infection or urolithiasis. Physical examination revealed a thumb head size induration in his left testis. Complete blood count and testicular tumor markers were within normal ranges and urinalysis was normal. Various imaging tests, such as ultrasound, computed tomography and magnetic resonance imaging, showed a round tumor with distinct boundary between the tumor and the normal testicular tissue in his left testis (Figure 1). The right testis was normal. Since we suspected benign tumor such as epidermoid cyst in this case, we tried to enucleate the tumor to preserve the testis. The tumor was easily separated from the normal testis. The surgery was completed once the tumor was Department of Urology, Wakayama Medical University, Wakayama, Japan. *Correspondence: Department of Urology, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan. Tel: +81-73-441-0637. Fax: +81-73-444-8085. E-mail: keito608@wakayama-med.ac.jp. Received July 2016 & Accepted April 2017 Shimpei Yamashita,* Hidetoshi Umemoto, Yasuo Kohjimoto, Isao Hara Xanthogranulomatous orchitis has been reported to be an extremely rare inflammatory change caused by infection and is difficult to distinguish from testicular tumor. We report a 28-year-old man who presented with a lump in his left testis after a blunt testicular trauma. Based on a series of imaging tests, we suspected benign tumor such as ep- idermoid cyst and performed tumor enucleation (testis-sparing surgery) on the patient. Histopathological findings showed xanthogranulomatous orchitis. It is assumed that xanthogranulomatous orchitis in this case was caused by blunt testicular trauma and this is the first successful case of xanthoglomatous orchitis in salvaging the testis. CASE REPORT Keywords: testis; testicular tumor; trauma; xanthoglomatous inflammation. Figure 1. Magnetic resonance imaging showed a round tumor with distinct boundary between the tumor and the normal testicular tissue in the patient’s left testis. (a) T1-weighted image. (b) T2-weighted image. Vol 14 No 03 May-June 2017 3094 Figure 2. Foamy macrophages accompanied by lymphocytes and plasma cell infiltration. HE X 100. confirmed benign via rapid pathological diagnosis. The resected specimen was a yellow necrotic mass with a diameter of 2 cm. Histological examination revealed the lesion consisted of a dominant infiltrate of foamy macrophages interspersed with a minor component of lymphocytes and plasma cells (Figure 2). Based on this inflammatory pattern, a diagnosis of XGO was made. Discussion We present a case of XGO which was caused by a blunt testicular trauma. Table 1 summarizes the data of 22 published cases. Median age was 51.3 years old and XGO was considered to be caused by either ascend- ing or hematogenous infection. The whole testis was replaced with fleshy tissue in 21 (95.5%) of the cases and inguinal radical orchiectomy was performed in all cases. In contrast, the present case differs from those previous cases. First, it is assumed that XGO in this case was caused by blunt testicular trauma as the patient ex- perienced dull pain in his left testis since the trauma occurred and subsequently observed a lump a month after. All published XGO cases were caused by infec- tion. However, in the present case, there was no sign of infection and urinalysis was normal. While there was a case of xanthogranulomatous pyelonephritis (XGN) which was reported to be caused by blunt trauma(7), the present case appears to be the first case of XGO caused by trauma. Although the exact mechanism of a trauma leading to xanthogranulomatous inflammation is still unknown, the following two hypotheses are considered. One hypothesis is that macrophages have infiltrated the hematoma caused by the trauma, resulting in XGO. The other hypothesis is that macrophages have infiltrated the necrotic tissue caused by blood vessel damage. The exact mechanism for causing xanthogranulomatous in- flammation calls for future investigation. Second, inflammatory tumor occurred in the normal testicular tissue and the patient underwent testis-sparing surgery. XGN accounts for lesser than 1% of chronic pyelonephritis and is classified into two categories. One is diffuse type in which the whole kidney is replaced with granulomatous tissue (about 85%). The other one is focal type in which granulomatous tissue forms a mass in normal renal tissue (about 15%)(3). The pres- ent case suggested that there is also focal type of XGO. Almost all the cases of XGO (21/22 cases) were diffuse type where normal testicular tissues were not found. Xanthogranulomatous orchitis mimicking tumor-Yamashita et al. Table 1. Summary of 22 published cases of xanthogranulomatous orchitis Author Journal Total Age Diffuse or Infection type Treatment patients Focal Akaza,H. et al. JPN.J.Clin.Urol. 1997; 31: 1023-1026. 2 64,63 Diffuse Ascending inguinal radical orchiectomy in both cases Iguchi,A. et al. JPN.J.Clin.Urol. 1985; 31: 1023-1027. 1 51 Diffuse Hematogenous inguinal radical orchiectomy Usamentiaga, E. et al. Urology. 1998; 52: 891-892. 1 35 Focal Ascending inguinal radical orchiectomy Vaidyanathan, S. et al. Spinal Cord. 2000; 38: 769-772. 1 21 Diffuse Ascending inguinal radical orchiectomy Hajiri, M. et al. Ann.Urol(Paris). 2001; 35: 237-239. 7 30-75 Diffuse Ascending inguinal radical orchiectomy in all cases Yap, R. L. et al. Urology. 2004; 63: 176-177. 1 64 Diffuse Ascending inguinal radical orchiectomy Nistal, M. et al. Arch. Pathol. Lab. Med. 2004; 128: 911-914. 2 58,79 Diffuse Ascending inguinal radical orchiectomy in both cases Dermirci, D.et al. Int. J. Urol. 2004; 11: 686-688. 1 21 Difffuse Hematogenous inguinal radical orchiectomy Salako, A. A. et al. Int. J. Urol. 2006; 13: 186-188. 1 24 Diffuse Ascending inguinal radical orchiectomy Al-Said, S. et al. Int. J. Urol. 2007; 14: 452-454. 1 44 Diffuse Hematogenous inguinal radical orchiectomy Hill, J. R. et al. Urology. 2008; 72:461. e11-13. 1 68 Diffuse Ascending inguinal radical orchiectomy Rifat Mannan, A. A. et al. Med. Princ. Pract. 2009; 18: 418-421. 1 65 Diffuse Hematogenous inguinal radical orchiectomy Val-Bernal, J. F. et al. Pathol. Res. Pract. 2012; 208: 62-64. 1 55 Diffuse Ascending inguinal radical orchiectomy Gakiya M. et al. Int. J. Urol. 2013; 75: 90-94. 1 79 Diffuse Hematogenous inguinal radical orchiectomy Present case 1 28 Focal tumor enucleation Case Report 3095 Also, the patients underwent inguinal radical orchiec- tomy because it was difficult to rule out the possibili- ty of malignant testicular tumor. However, although it was a focal-type XGO in the present case, the patient was initially diagnosed with epidermoid cyst, and was arranged to undergo tumor enucleation, also known as testis-sparing surgery. One focal-type XGO patient was reported to have underwent radical inguinal orchiecto- my due to multiple tumors in his testis(8). Therefore, to the best of our knowledge, this is the first successful case of XGO in salvaging the testis. The present case suggests that it is highly challenging to distinguish fo- cal-type XGO from epidermoid cyst, which has rela- tively high generating frequency among benign tumors in the scrotum, based on radiological findings. CONCLUSIONS The present case suggested that trauma could cause xanthogranulomatous inflammation. As there is a focal type of XGO, it is therefore difficult to clearly differen- tiate it from epidermoid cyst. Hence, if epidermoid cyst is suspected, noting the possibility of a focal type of XGO and performing testis-sparing surgery should be taken into consideration. CONFLICT OF INTEREST None declared. REFERENCES 1. Wiener LB, Riehl PA, Baum N. Xanthogranulomatous epididymitis: a case report. J Urol. 1987;138:621-2. 2. Al-Said S, Ali A, Alobaidy AK, Mojeeb E, Al- Naimi A, Shokeir AA. Xanthogranulomatous orchitis: review of the published work and report of one case. Int J Urol. 2007;14:452-4. 3. Chlif M, Chakroun M, Ben Rhouma S, et al. Xanthogranulomatous pyelonephritis presenting as a pseudotumour. Can Urol Assoc J. 2016;10:E36-40. 4. Chung MK, Seol MY, Cho WY, Seo HK, Kim JS. Xanthogranulomatous cystitis associated with suture material. J Urol. 1998;159:981-2. 5. 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