A 56-year-old female was admitted to our clinic with a complaint of multiple masses in her left neck region. The past medical history of the patient included a left nephrectomy for renal cell carcinoma (the pathological analysis revealed clear cell + chromophob cell carcinoma) in 2000, otherwise normal. A physical examination of the patient revealed multiple painless cervical masses at different lymphatic levels in the left cervical region [].\nLaboratory findings were as follows, hemoglobin:14 gr/dl, hematocrit: 41,1%, erythrocyte count: 5.180.000/ mm3, leucocyte count: 6.390 / mm3 (66.4% neutrophils, 23.9% lymphocytes, and 7.2% monocytes), and erythrocyte sedimentation rate 31 mm / 1 hour. Urine analysis was normal. The Brucella agglutination test, and the MONO, VDRL, ANA, ANTİ-DNA, ASMA, AMA, ASO, and CRP tests were normal. The thyroid function tests were normal. The scintigraphic bone scan imaging was negative for metastatic lesions. Thyroid ultrasonographic examination and high resolution Pulmonary imaging were also found to be negative for metastasis. An abdominal ultrasonograpic examination showed a nephrectomy scar on the left side, but was otherwise normal. Ultrasonographic examination of the neck detected five lymphadenopathies of different sizes with the greatest dimension of 3 × 3 cm. The magnetic resonance imaging (MRI) scan also confirmed the ultrasonographic findings, and post contrast scanning showed heterogen and noduler contrast. Pathological examination of the fine needle aspiration biopsy (FNAB) of the lymphadenopathy that was greatest in dimension showed renal cell carcinoma (RCC), clear cell type.\nIn December 2006, left functional neck dissection was performed. Totally 23 lymphadenopathies were counted in the surgical specimen. The greatest lymph-node metastasis appeared as a thick, irregularly walled cystic mass, with a minimally enhancing or dense surrounding reaction that effaced the adjacent tissue planes []. In the pathological examination of the dissected lymphadenopathies, it was found that a third of them in the jugulodigastric region were metastatic renal cell carcinoma []. Postoperative radiotherapy to the neck region was performed. In the second and fourth months after the second operation, she has no evidence of recurrence in the neck region.
In June 2019, a 53-year-old man was admitted to a local hospital due to a palpable “right neck mass”. He had no fever, dizziness, fatigue, abdominal pain, backache, frequent urination, urgency, or changes in urine color. There was no other positive clinical sign on physical examination. No family history of hereditary diseases was detected. After surgical resection, a metastatic squamous cell carcinoma was diagnosed pathologically (, left panel). In the following PET-CT (Positron Emission Tomography-Computed Tomography) scan showed nodular iso-density foci in the upper pole of the left kidney, with a diameter of about 28.5 mm, SUVmax value of 8.3, increased FDG (fluorodeoxyglucose) metabolism, indicative of malignant lesions, and semi-oval infarct foci in the center of the right kidney. On July 29, 2019, renal puncture was performed, and the pathological diagnosis was epithelial tumor based on the immunohistochemical positive results of relevant markers. SPECT/CT (Single Photon Emission Computed Tomography) showed no obvious abnormalities in blood flow perfusion, uptake and excretion in both kidneys.\nFor further surgical treatment, the patient was transferred to our hospital on August 12, 2019. The renal artery CTA (Computed Tomographic Angiography) results showed an oblong iso-density foci of about 3.4 * 2.1 cm in the middle of the right kidney, and a 4.4 * 4.2 cm-like circular iso-density lesion in the upper left kidney (). The local boundary was unclear from the adjacent renal parenchyma. It was slightly protruded on the surface of the renal parenchyma, and the lesion was slightly uneven and enhanced by enhanced scan. There was no obvious abnormality in the diagnosis of bilateral renal artery CTA. Kidney magnetic resonance imaging (MRI) confirmed a 2.9 * 1.5 cm circular abnormal signal lesion in the middle of the right kidney and a 3.6 cm diameter circular abnormal signal lesion in the upper pole of the left kidney, which was isointense on T1-weighted imaging (T1WI), a low signal area on fST2WI, and hyperintense on DWI. The signal of the ADC map was reduced, and a slight uneven enhancement was seen by enhanced scan. Based on the above findings, the possible diagnosis was a malignant tumor of the kidney.\nOn August 19, 2019, a laparoscopic radical nephrectomy (left) was performed under general anesthesia. On December 12, 2019, the patient was admitted to the hospital due to a “right kidney mass”. After completing the relevant examinations, the “Da Vinci Robot-Assisted Laparoscopic Partial Right Nephrectomy” was successfully performed. No complication was observed and the patient was discharged six days after surgery. The patient’s condition currently remains stable. PET-CT scan re-examination found no local recurrence or distant metastasis one year after the operation.\nHistological examination of the radical nephrectomy specimen of the left kidney showed a mixed pattern of mucinous tubular and spindle cell carcinoma (MTSCC) with papillary adenoma (, middle panel). Microscopy examination of the partial nephrectomy of the right kidney revealed a papillary renal cell carcinoma (PRCC) (, right panel). The histological morphology and immunohistochemical results of renal tumor were different from those of neck tumor. PAX8 staining showed positive expression ().\nTo further investigate their genetic characteristics, whole exome sequencing (WES) was performed separately. A total of 304 putative somatic variants of 225 genes were identified in neck tumor tissues, of which 10 were identified as driver gene mutations, including CDKN2A, KMT2D and NSD1 mutations that are common drivers of head and neck squamous cell carcinoma (HNSC) (). Similarly, the WES results of renal tumor samples revealed 361 somatic variants in 219 genes in the left kidney and 270 somatic variants in 207 genes in right kidney, including five and four driver gene variants, respectively ( and ). The three lesions have both private and shared mutation genes shown in . Similarly, 51, 58 and 47 shared gene variants were detected respectively between left & right kidney, left kidney& neck, and right kidney & neck. Thirty-eight common mutated genes were shared in all three tumor tissues. For the driver gene mutations, the right nephropathy foci shared one driver gene mutation with the left kidney (WT1) and the neck lesions (CREBBP), respectively. But no driver mutated gene was shared in all three tissues ().\nIn addition, a clonal evolution analysis was performed to examine the heterogeneity of tumor evolution among different lesions. We used a previously reported hierarchical Bayesian clustering model () to define clones and subclones based on clusters of SNVs sharing similar cancer cell fractions (CCF). CCF distributions are shown in . These clones and subclones were shared between the spatially distinct lesions. Correspondent clonal components also existed in different lesions, especially some driver gene mutations, such as NFKB2, WT1, GTF2I, etc. The clone evolution analysis showed that the clone components of the initial left renal primary lesion and the final cervical squamous cell carcinoma lesion were different. The left renal tumor was mainly composed of clones 3, 4, and 7, the right renal tumor was mainly composed of clones 2, 3, and 6, while the cervical mass was mainly composed of clones 4 and 6 (). Therefore, the primary clones in the metastatic lesions may not be derived from the primary clones in the left kidney tumor. Instead, they may have originated from the subclones generated before the diagnosis. Some driver gene variants detected in clones with different lesions were unique and some were shared. The putative dynamic mutation profiles during the disease course are represented in . These results can serve as a strong complement to histopathological findings, suggesting that these lesions may have evolved from the original focus, although there are differences in the pathological morphology of different lesions.