Lipoma arborescens is a chronic, slow-growing, intra-articular lesion of benign nature, which is characterized by villous proliferation of the synovium, with replacement of the subsynovial connective tissue by mature fat cells. It usually involves the suprapatellar pouch of the knee joint. It is not a neoplasm but is rather considered a nonspecific reactive response to chronic synovial irritation, due to either mechanical or inflammatory insults. We report three cases of lipoma arborescens affecting the knee, the first in a young male without previous history of arthritis or trauma, the second in a 58-year-old male associated with osteoarthritis, and the final in a 44-year-old male diagnosed with psoriatic arthritis, which cover the entire pathologic spectrum of this unusual entity. We highlight the clinical findings and imaging features, by emphasizing especially the role of MRI, in the differential diagnosis of other, more complex intra-articular masses.

Introduction: Bilateral testicular tumors are very rare, accounting for 1%–5% of all testicular germ-cell tumors (TGCTs). The vast majority of primary bilateral TGCTs are metachronous, with synchronous tumors comprising approximately 0.5%–1% of all cases. Those occurring synchronously share mostly the same histological pattern, predominantly seminoma, with synchronous bilateral TGCTs (SBTGCTs) with discordant subtypes being extremely rare. Case presentation: We present the case of a 20-year-old male complaining of a palpable painless right testicular mass incidentally noticed during sexual intercourse. Ultrasonography (US) and magnetic resonance imaging (MRI) of the scrotum demonstrated bilateral testicular lesions, while staging with contrast-enhanced computed tomography (CT) exhibited normal findings. Right radical orchiectomy and left testis-sparing surgery (TSS) with concomitant onco-testicular sperm extraction (onco-TESE) were initially performed. Histology of the right testis revealed a mixed germ-cell tumor, consisting of seminoma and embryonal carcinoma, while that from the left testis disclosed embryonal carcinoma and intratubular germ-cell neoplasia unclassified (IGCNU) infiltrating the surgical margins. Hence, left orchiectomy was subsequently scheduled with histology unveiling IGCNU in the greatest part of the remaining testicular parenchyma. Following adjuvant chemotherapy, with bleomycin, etoposide, and cisplatin (BEP), the patient received testosterone replacement therapy and remained free of recurrence at an 18-month follow-up. Conclusion: This case highlights both the rarity of a bilateral testicular tumor’s synchronous appearance and its extremely infrequent discordant histopathology. A comprehensive review of the major series of SBTGCTs with discordant histology cited in the literature is additionally presented.

The synchronous occurrence of renal cell carcinoma and urothelial carcinoma of the renal pelvis in the same kidney is extremely rare, although previously reported. With this study we aim to present our case and provide a literature review on this entity. An otherwise healthy 43-year-old military male with the chief complaint of left plank pain was seen in the office. Imaging revealed the presence of a 3.5 cm left renal mass. Left laparoscopic radical nephrectomy was performed for presumed renal malignancy. Pathology confirmed the presence of a clear cell RCC and revealed an area of low-grade UC arising from the ipsilateral renal pelvis, not visible in the preoperative imaging. Furthermore, a Pubmed database search in English language was conducted, up to June 2021, to identify the rate of simultaneous RCC and UC of the renal pelvis or ureter in RN specimen performed for presumed RCC or renal malignancy and subsequent management in these cases. A total of 53 articles reporting on 56 patients with synchronous ipsilateral RCC and UC of the renal pelvis were identified, together with our case. Eight cases (14%) were initially managed with RN, thereby requiring further management of the ureteral stump. Of these, six (75%) were managed with distal ureterectomy, one (12.5%) with active surveillance of the ureteral stump, while one case (12.5%) did not report subsequent management. To our knowledge, we present the youngest patient recorded in the literature, with this histology combination presenting synchronously in the same kidney. Although uncommon, the final pathology report may reveal neoplasms of dissimilar histology that may involve the renal pelvis. It is crucial for urologists and pathologists to be vigilant of such cases during a solid renal mass workup. Additional therapeutic adjustments may be necessitated, derailing the initial treatment plan.

Hydrocele is the most common benign cause of painless scrotal enlargement and only very rarely can be reactive to an underlying testicular tumor. We present the case of a healthy young man, complaining of mild left scrotal discomfort and swelling. Physical examination revealed a non-tender fluctuant left scrotum and serum tumor markers were normal. Scrotal ultrasonography (US) showed a normal right hemiscrotum and testicle and a fluid collection among thickened irregular septations in the left hemiscrotum, a finding which was considered as a complex hydrocele. Intraoperatively the presumed “complex hydrocele” was in fact a multicystic testicular tumor. We proceeded with orchiectomy through the scrotal incision and pathology revealed a mixed germ cell tumor of the testis consisting of cystic teratoma, in situ germ cell neoplasia unclassified (IGCNU) and Sertoli cell tumor. This is the first reported case of this type of testis tumor presenting as complex hydrocele. The aim of this case presentation is to underline the need for an accurate preoperative diagnosis in cases of suspected scrotal pathology in young males.

OBJECTIVE. The purpose of this study is to describe the MRI findings and treatment decisions and outcome for Morel-Lavallée lesions (MLLs) of the knee and to investigate whether evidence exists to support an increased frequency of such lesions on the medial or lateral side by performing a cadaveric experiment. MATERIALS AND METHODS. In a 4-year period, 24 MRI studies of 24 consecutive patients (16 male patients and eight female patients) with knee MLLs were retrospectively reviewed. Patient demographic characteristics, treatment decisions and outcome, and associated injuries were recorded. The location of the MLL was categorized as medial, lateral, or global. Lesions were categorized according to an established MRI classification. During the cadaveric experiment, the compartmental pressures of the medial or lateral aspect of the knee were monitored in 20 cadaveric knees. The chi-square test, t test, and Pearson correlation were used for statistical analysis. RESULTS. MLLs were located medially in 16 patients, laterally in two patients, and globally in six patients. The medial location was significantly more common than a lateral or global location (p < 0.05). MLLs were classified as type I in 14 patients, type II in eight patients, and type III in two patients. MRI type was correlated with the chronicity of injury (r² = 0.614; p = 0.0014). Fractures were the most common associated injuries, occurring in seven of 24 patients. In 17 patients, all of whom had conservatively treated type I or type II lesions, complete resolution of the MLL occurred. The maximum compartmental pressures were significantly higher on the lateral side than on the medial side (p < 0.0001). CONCLUSION. Knee MLLs have a predilection for the medial side, which may be attributed to the lower resistance in this location, and they have variable patterns on MRI, which correlate with chronicity. Conservative treatment of type I and II lesions seems effective.