RCC and TCC represent the majority of renal malignancies in adults comprising together 90–95% [3]. The coexistence, however, of the two most common histological subtypes of renal tumors in the same kidney is extremely rare, approximating 0.14% as per a previous study [4].
Concurrent RCC and TCC of the renal pelvis present with a mean age of 64.5 years, more commonly in the left side, such as in our case, and are twice as common in males, resembling the epidemiology of independent RCC or TCC of the kidney, as demonstrated by Hart et al. in a review of 23 cases [5]. Strikingly enough, our patient was 43 years old, making him the youngest case on record to the best of our knowledge. Moreover, it represents the first report in active military personnel. Previously, Kline et al. had reported on a 47-year-old patient in an era when CT urography was practically nonexistent [6].
In the same retrospective study by Hart et al., cigarette smoking was implicated in 24% of the cases [5]. TCC of the renal pelvis may be associated with the abuse of phenacetin-based compounds. Anseline et al. in 1977 described this histological combination in a woman with analgesic nephropathy [7], in accordance with Bengtsson et al. initial findings in 1968 [8]. Our patient denied the use of analgesics and exposure to other known renal carcinogens apart from tobacco. Moreover, Park et al. proposed that c-MET and p53 may be associated with the development of papillary TCC of the renal pelvis, based on their immunohistochemistry findings [9].
Interestingly, we are witnessing a paradigm shift in the preoperative diagnosis of such cases. Traditionally, the renal pelvic tumor was diagnosed first, using retrograde pyelograms, during the workup of hematuria, and the RCC was an incidental pathology finding [4]. Nowadays, most renal tumors and more than 50% of RCCs are detected accidentally due to the US and CT’s widespread use for other medical indications [10]. Consequently, similarly to our case, detection of an asymptomatic RCC usually precedes that of TCC.
Regarding management, surgical treatment of RCC and upper tract UC are fundamentally different. RCC is managed by radical or partial nephrectomy, with the latter suggested mainly for localized T1 RCC [10]. Upper tract UC management, on the other hand, relies on risk stratification to select those patients who will benefit more from a kidney-sparing treatment. Histological and cytological grades of cancer cells are crucial factors, although not the only ones, to consider for risk stratification. With that being said, kidney-sparing surgery (KSS) for low-risk disease and RNU with bladder cuff excision for high-risk disease are recommended [11].
Due to the unfavorable location of close proximity to the renal hilum, we decided to proceed with a laparoscopic RN, even though we had to deal with a T1 tumor.
In view of the incidental UC in the renal pelvis after RN, management of the remaining ureteric stump remained a therapeutic dilemma. Previous series have shown recurrence rates ranging from 20 to 58 % in the ureteral stump after incomplete nephroureterectomy for TCC of the upper tract and seem to increase proportionately to the length of the remaining ureter [12]. On top of that, a study from Mayo Clinic suggested that grade 2 tumors carry a 30 % rate of ipsilateral tumor recurrence, meriting a radical nephroureterectomy. Conversely, the less frequent ipsilateral recurrence in grade 1 tumors may allow a less radical approach [13].
In our case of a low-grade TCC of the renal pelvis found after RN, one could argue in favor of surveillance instead of a more extensive surgical treatment. An interesting case of active surveillance with cystoscopy, ureterograms, ureteral washings, and ureteroscopy of the ureteral stump is reported by Michel and Belldegrun [14]. Of note, the patient must be aware of the stringent follow-up that active surveillance entails to make an educated choice. Our patient elected to complete the surgical treatment to avoid this strict surveillance and eliminate anxiety around a potential recurrence.
Cancer stem-like cell (CSC) markers, such as cluster of differentiation 44 (CD44) and aldehyde dehydrogenase 1 A1 (ALDH1A1), may give insights into the prognosis of urologic malignancies [2]. Lu et al. reported the first patient with recurrence of both RCC and UC, in the ipsilateral adrenal and bladder respectively, despite the use of adjunct chemotherapy and clear surgical margins. The high incidence of metastatic recurrences may be associated with the abnormal expression of CSC markers in primary or recurrent lesions, before and after chemotherapy, as demonstrated in Lu’s case [2]. However, their role as markers of chemotherapy resistance or potential therapeutic targets remains to be seen.