A 28-year-old female patient (K.) was admitted to N. N. Blokhin National Medical Research Center of Oncology in June 2016 after being referred from another hospital for further diagnosis and being treated for multiple renal cell tumors. Patient K. gave informed consent to undergo diagnostic procedures and treatment, as well as to participate in the study, and for the presentation of relevant clinical and molecular data in this paper. This case report was approved by the local Ethics Committee at Sechenov University. Based on the medical records, the patient had pituitary adenoma with endo-, supra-, infra-, and latero-sellar growth with partial descending optic atrophy on the left in 2012. At that time, the disease was clinically manifested by broadening of the feet and fingers, increased sweating, cysts and diffuse changes in the thyroid gland, and an increase in the level of growth hormone. The pituitary adenoma was partly removed via endoscopic transsphenoidal surgery in 2012, and she was treated with somatostatin analogs. At the time of the follow-up examination in 2016, no pituitary adenoma recurrence was detected; she was recommended to continue taking the somatostatin analog (octreotide depot) 20 mg intramuscularly once every 28 days in combination with bromocriptine 2.5 mg per day. At the same time, multiple neoplasms were detected in both kidneys. Family history was negative. The patient and her immediate family had no oncological diseases at a young age or other signs suggesting any known cancer syndrome. At the time of the hospitalization of patient K. in the N. N. Blokhin National Medical Research Center of Oncology, her parents and the child did not have cancer symptoms.
Patient K. was examined at Blokhin National Medical Research Center of Oncology. Computed tomography with intravenous contrast detected three 1-2 cm tumor lesions with the active accumulation of the contrast agent in the right kidney. In the left kidney, there were four tumor lesions: a 3.5 x 3.0-cm mostly cystic tumor with a soft-tissue component, with parietal accumulation of the contrast dye in the middle one-third portion; a tumor with a diameter of 1.3 cm at the upper pole; a tumor with a diameter of 1 cm in a subcapsular location in the middle one-third; and a tumor of 1.3 cm in diameter at the lower pole; these tumors similarly accumulated the contrast dye. Various tests were performed, including skeletal scintigraphy, computed tomography of thoracic organs, and ultrasound of the abdominal and pelvic organs, which showed no sign of distant tumor process. Blood count, chemistry, and clotting tests were carried out prior to surgery and showed no clinically significant abnormalities. Complex renal scintigraphy revealed an insignificant decrease in radionuclide clearance; preoperative creatinine clearance was 84 mL/min.
Based on the obtained diagnostic data, a multidisciplinary board was held, with the participation of surgical oncologist, oncologist, pathomorphologist, a specialist in radiation diagnostics and urologist. Taking into account the current recommendations of the European Association of Urology and the current standards of medical care of the Ministry of Health of Russia for patient K. with bilateral localized kidney cancer, the tactics of stepwise tumor resection with preliminary examination using computed tomography with contrast was chosen.
Partial nephrectomy was performed in two steps. The right kidney was resected during the first step. Intraoperative findings included four tumors of 0.5-1.3 cm in dimension in the lower one-third, three tumors of 0.5-1.0 cm in the middle one-third, and three tumors of up to 1.5 cm in the upper one-third of the right kidney. Through hilar occlusion, all detectable tumors were consecutively removed with a margin of visually unchanged tissue and adjacent pararenal fat under intraoperative ultrasound guidance. The sides of each resection site were sutured together. The kidney ischemia time was 28 min, total surgery duration was 135 min, and blood loss was 300 mL. Postoperative complications did not occur; serum creatinine increased insignificantly to 118 mumol/L. Patient K. was discharged in satisfactory condition on day 13 after surgery.
Two months later, in August 2016, patient K. was again admitted to Blokhin National Medical Research Center of Oncology to undergo a second surgery. Computed tomography scanning of the abdomen with intravenous contrast was performed before surgery and showed a deformed right kidney with two low-density sites that had uneven outlines and were 3.0 x 2.2 cm in total (postoperative changes). At least seven contrast-accumulating nodular masses were detected in the left kidney. Compared to the previous scan, which was performed 2 months earlier, one large mass had increased to 4.0 x 3.2 cm (previously 3.7 x 3.0 cm) at the posterior surface, whereas the other masses remained unchanged (Figure 1). Complex testing showed no findings suggesting metastasis. In surgery, nine tumors were consecutively removed with a margin of visually normal tissue from the left kidney with hilar clamping (ischemia time 28 min). Blood loss was 300 mL, and surgery duration was 150 min. The patient developed a fever (38 C) 9 days after the surgery. Due to the dilation in the collecting system of the right kidney, a JJ ureteric stent was placed. The inflammatory infection worsened, warranting a change in the antibacterial therapy and a nephrostomy tube was placed on the right. Signs of acute pyelonephritis were eliminated. The nephrostomy tube was removed 18 days after the surgery. By the end of the surgical treatment, the creatinine clearance was 32 mL/min, and serum creatinine was 168 mumol/L. Patient K. was discharged in a satisfactory condition. Regular follow-up tests were performed in subsequent years. In February 2019, no sign of relapse or disease progression was detected in control complex testing, which included magnetic resonance imaging of the abdominal organs.
All tumor masses were removed from the right kidney during the first surgery. Microscopic examination revealed that they were structurally similar, and the tumors were identified as type I papillary RCC, Fuhrman grade 2 (Figure 2). Tumor cell growth was not detected in the pararenal fat. The nine tumors removed from the left kidney during the second surgery were also structurally consistent with type I papillary RCC, Fuhrman grade 2 by histology.
Because multiple type I papillary RCC tumors developed synchronously and bilaterally and affected a young patient, molecular genetic testing was carried out for patient K. in the period between the first and second surgeries. Note that it would be more advisable to do this before the first stage of the surgical intervention, so that in case of a positive test result, there would be an extra argument in favor of organ-preserving treatment, but the organizational peculiarities of the hospital care and the time frame for molecular genetic diagnostics made it possible to conduct a genetic study only during the first stage of treatment.
Genomic DNA was isolated from a peripheral blood sample with a DNA-sorb-B kit (NextBio, Moscow, Russia). Fragments of MET exons 15-21 were PCR-amplified using primers with previously published sequences. The reaction mixture contained 50-100 ng of genomic DNA, 2.5 mM MgCl2, 1.5 mM each dNTP, 2 pmol of the forward and reverse primers, 1 unit of thermostable Taq polymerase, and 5 muL of 5x PCR buffer (Interlabservice, Moscow, Russia); the total volume was 25 muL. Amplification was performed as follows: 95 C for 1 min; 35 cycles at 95 C for 45 s, 61 C for 25 s, and 72 C for 30 s; and final elongation at 72 C for 50 s. After amplification, the PCR product was treated with 1 unit of alkaline phosphatase and 4 units of Escherichia coli exonuclease I to eliminate free primers and dNTPs. The product was then subjected to Sanger sequencing using a BigDye Terminator v. 3.1 Cycle Sequencing kit and 24-capillary 3500xl sequencer (Thermo Fisher Scientific, Waltham, MA, USA).
The single-nucleotide substitution c.3328G>A was found in exon 16 in a heterozygous state (Figure 3). This substitution causes the missense mutation p.V1110I (Human Genome Mutation Database accession no. CM990852, http://www.hgmd.cf.ac.uk/ac/index.php). The germline mutation has been described as a cause of HPRC, occurs in the ATP-binding site of the HGF receptor, leads to its activation, and exerts a transforming effect in fibroblast cultures in vitro. The somatic p.V1110I mutation has similarly been found in a sporadic type 1 papillary RCC (Catalog of Somatic Mutations in Cancer accession no. COSM3724572, http://cancer.sanger.ac.uk/cosmic) and is considered as a pathological factor associated with activation of the HGF receptor. These results confirmed the diagnosis of type I HPRC (OMIM 605074) in patient K. Following the results of the analysis, genetic counseling was carried out and mutation carriage testing was recommended for family members of the first line of kinship. Patient K. was also advised to consult a geneticist and a urologist once every 6-8 months. At the time of writing, there is no information about a confirmed mutation in any of the relatives of patient K. Together with a negative family cancer history, this suggests that the identified germline mutation can be classified as de novo.