Primary sinonasal renal cell-like adenocarcinoma: a case report and review of the literature

Primary sinonasal renal cell-like adenocarcinoma (SNRCLA) is an extremely rare neoplasm with unique clinical and pathological features. At present, there is no summary of its clinical and pathological characteristics. We treated one case and reported to here. Review the domestic and foreign literature, summarize its clinical pathological characteristics and diagnosis and treatment. Case A 69-year-old female presented with repeated epistaxis, nasal obstruction of 2-years’ duration. Computed tomography (CT) was performed revealing an irregular mass of the right nasal cavity involving choana and nasopharynx. The patient was treated with endonasal endoscopic resection. Histologically, SNRCLA was very similar to clear cell renal cell carcinoma (RCC), the tumor cells were round or polygonal in size with abundant clear cytoplasm and uniform nuclei. The tumor cells positive for CK7, Vimentin, EMA, S-100, Ki-67 (5% +) and negative for CEA, P53, P63 by immunohistochemical staining,. The patient is free from recurrence over 27 months after the surgery.


Introduction
Primary sinonasal renal cell-like adenocarcinoma (SNRCLA) is quite rare and limited number cases reported. "renal-cell like" was originally described by Zur et al [1] in 2002, who noted its resemblance to the clear-cell type of renal cell carcinoma (RCC) but with no evidence of RCC after a detailed inspection. Herein, we presented a case of primary SNRCLA and described its clinical, histopathologic, immunophenotypic, and prognostic features.

Case Report
A 69-year-old woman presented with a 2-years history of right-sided epistaxis, she complained of progressive right nasal obstruction without any symptoms such as headaches, tinnitus, diplopia, and numbness of face. Computed tomographic (CT) scan showed an irregular mass in the right nasal extending to the right choana and nasopharynx, no invasive bone destruction (Fig. 1). To exclude metastatic RCC, CT scan of abdomen and pelvis were performed, no primary renal tumor was identi ed. Chest CT and whole-body bone scan using single photon emission computed tomography (SPECT) were normal. The patient treated with endonasal endoscopic resection followed by adjuvant chemotherapy with paclitaxel and cisplatin. Histopathology revealed the tumor consisted of transparent cells arranged in nests and separated by brocellular and hyalinized brous septa. The nuclei were uniform and small round, with abundant clear cytoplasm, centrally or eccentrically located with inconspicuous nucleoli. Mitosis and necrosis were absent. Immunohistochemica stain revealed the tumor cells positive for cytokeratin (CK), CK5/6, CK7, CK8/18, Vimentin, EMA, S-100, Ki-67 (5% +) and negative for CEA, CgA, Syn, P40, P53, P63, CD34, HMB45, Melan-A, LCA (Fig. 2). The radiological, histological, and immunohistochemical foundings were consistent with primary SNRCLA. There was no recurrence over 27 months after aggressive treatment.
In the group of 20 patients, including our present case, have been identi ed SNRCLA ( Table 1). The clinical presentation is no difference of other types of nasal neoplasm. The ages of the patients ranged from 22-89 years, with a median age of 62.5 years.
There was predominant in women with 13 females and 7 males. The presenting symptom was epistaxis and nasal obstruction in the majority of patients, headache, epiphora, hyposmia and tinnitus were also reported, although not speci c for SNRCLA. The primary location were as follows: nasal cavity (11, 55%); Sinonasal (6, 30%), only 3 cases in nasopharynx have been reported. . Tumor cells of SNRCLA were round or polygonal in size, arranged in a solid nest-like manner, with abundant clear cytoplasm and uniform nuclei, centered or biased on one side, mitosis is rare, rich glycogen and lipoid, clear cell membrane, obvious boundary and slight pleomorphism. As summarized in Table 2,most of previously reported SNRCLA case were positive for CK7 (13/14), EMA (8/8), and negative for vimentin (7/13), S100 (9/15). The current case was positive for CK7, vimentin and S100. Most of SNRCLA characteristically expresses CK7, vimentin expression is variable and the Ki-67 proliferation index is usually low. In previous reports, only 9 of the 19 tumors reported to date were initially diagnosed as SNRCLA. About 9 of 19 tumors were initially diagnosed as clear cell carcinoma and 1 of 19 diagnosed a low-grade adenocarcinoma. The clinical outcomes of SNRCLA carries a favorable prognosis. 18 patients (including ours) had follow-up examinations, the median follow-up duration was 23 months (range, 2-96 months). 15 patients were treated with primarily surgery, of which 9 patients received adjuvant radiotherapy, 2 patients received radiotherapy and chemotherapy, 1 patient received radiotherapy alone, and 1 patient received chemotherapy alone. Only 2 patients have been local recurrence, 1 patient recurrence at 3 and 5 years after surgical excision [2], the other patient developed recurrence at 7 months after surgery and postoperative radiotherapy [4]. Neither regional lymph node involvement nor distant metastases has been documented. The most effective treatment is surgical resection, adjucant radiotherapy may not be necessary in patients with negative margins.
In conclusion, we have reported a rare case of primary SNRCLA which is regarded as a low grade tumor. Surgical resection is recommended as the mainstay of treatment, radiotherapy and chemotherapy are still controversial. Further studies on clinical information, radiology, cytology, and immunohistochemistry is helpful for diagnosing SNRCLA.  Figure 1 Head CT scan. CT scan shows a soft tissue mass lling the right nasal and extends posteriorly to the choana in soft tissue window (A) and bone window (B). CT = computed tomography.