Sinonasal Adenoid Cystic Carcinoma with Rare Renal Metastasis on Fluorodeoxyglucose Positron Emission Tomography Scan: A Case Report and Literature Review.

Adenoid cystic carcinoma (ACC) of sinonasal cavity is not the frequent entity. It is characterized by indolent growth and clinical course and high rate of recurrences, perineural spread, and late metastases. We represent a patient with rare renal metastasis from sinonasal ACC in pretreatment fluorodeoxyglucose positron emission tomography-computed tomography scan, and pathological confirmation has been obtained from both the primary and metastatic sites. Metastatic lesion was asymptomatic and found during the early course of disease. As per our knowledge, this is the second case report of sinonasal ACC with renal metastasis and the first case of metastatic ACC in patient prior receiving any type treatment.

Introduction

Adenoid cystic carcinoma (ACC) comprises <1% of all head and neck malignancies and 10% of all salivary gland neoplasms.[1] Most common location is the salivary gland and second most common in sinonasal cavity. Other sites of ACC origin are lacrimal gland, trachea, breast, lung, skin, vulva, and prostate.

ACC is the third most common sinonasal malignancy with the peak incidence in fourth and fifth decades. Common locations for sinonasal ACC in descending order are maxillary sinus, nasal cavity, ethmoid and sphenoid sinuses. Sinonasal ACC has the worst prognosis among all head and neck ACC. The most common sites of distant metastasis are lung followed by the liver and bone.

Case Report

We report a case of a 60-years-old male patient, presented to head and neck clinic with slow-growing left nasal cavity growth with the complaint of nasal obstruction, on-and-off epistaxis, and cheek swelling for the past 1 year. Biopsy of left nasal growth showed as poorly differentiated ACC of the left sinonasal cavity. The patient referred for 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) scan.

The patient was taken for PET-computed tomography (CT) scan on SIEMENS Biograph TruePoint 16-slice CT scanner after 60 min of 285 MBq 18F-FDG intravenous injection. Contrast neck magnetic resonance imaging (MRI) was also performed for the better anatomical evaluation of sinonasal lesion and the evaluation of perineural spread.

FDG PET-CT with side-by-side analysis of the contrast MRI of neck revealed large lobulated, expansile, heterogeneously enhancing, moderate-to-high grade FDG avid mass lesion occupying entire left side of sinonasal cavity, nasopharynx with cranial extension up to pterygopalatine fossa and masticator space through left pterygomaxillary fissure, as well as minimal extension into extraconal compartment of left orbit and also involving left inferior orbital fissure [Figure 1]. No perineural spread was seen in other skull base foramina. No metastatic cervical lymphadenopathy was detected.

Figure 1

Positron emission tomography-computed tomography fusion, contrast-enhanced computed tomography scan, and contrast magnetic resonance imaging axial (upper) and coronal images (lower) showing large lobulated, expansile, heterogeneously enhancing, moderate-to-high grade fluorodeoxyglucose avid left sinonasal cavity mass lesion with extensive and advanced locoregional disease

The whole-body PET-CT scan also revealed incidental findings of three hypovascular solid hypodense low-grade FDG avid well-marginated lesions in corticomedullary junction right kidney [Figure 2]. The patient had no any sign and symptoms related to urinary tract abnormality. No signs of hydronephrosis were seen. The contralateral kidney was unremarkable.

Figure 2

Positron emission tomography-computed tomography fusion and contrast-enhanced computed tomography scan coronal images (upper and middle rows) shows well-defined, heterogeneously low-grade fluorodeoxyglucose avid solid hypodense lesions at corticomedullary junction of the right kidney with maximum intensity projection images in lower penal

His ultrasonogram-guided renal lesion biopsy was conclusive of metastatic adenocystic carcinoma.

Discussion

Sinonasal ACC is 10%–25% of head and neck ACCs.[2] Sinonasal ACC is characterized by indolent growth and clinical course with higher rate of recurrences, perineural spread, and metastases.[3] Sinonasal neoplasms generally present with symptoms identical to inflammatory diseases such as obstruction, rhinorrhea, epistaxis, facial swelling, and headache. Associated dull pain, paresthesias, or nerve paralysis due to perineural spread is highly suggestive of ACC.

Distant metastases, mainly through perineural and hematogenous and rarely lymphomatous routes, are seen in 25%–40% cases and commonly affect the lung, bone, liver, brain, and very rare kidney.[4]

Surgery, radiation, or combinations of both are the treatment option; however, the choice depends on site, stage, histologic grade, and biologic behavior of disease. Surgery is feasible and even after achieving the clear margin, high likelihood of local recurrence, and distant disease over a period of years which contributes major cause of death rather than primary treatment failure.

Usually late occurrence of metastasis from ACC, even after many years of the primary tumor, has been known. And among them, renal metastasis is very infrequent, and few cases have been reported.

On reviewing the reported cases of renal metastatic ACC, we have found the most common site of the primary is salivary gland and few from lacrimal gland, lung, and breast [Table 1].

Table 1

Literature review of primary head and neck adenoid cystic carcinoma with renal metastasis

Santamaría et al. reported a case of renal metastasis after 14 years of surgery for the palatal primary ACC.[5]

Kala et al., after 8-year treatment (surgery and chemoradiotherapy) of the primary salivary gland ACC and occurrence of renal metastasis found on postradical nephrectomy histopathology evaluation for solitary renal mass.[6] Bacalja et al. reported a similar case of renal metastatic ACC after 14 years of primary lacrimal gland ACC surgery.[7]

Qiu et al. found reported a case of FDG PET-CT scan revealed a moderate-grade FDG avid single lesion of right kidney, and on right radical nephrectomy, it came as singular metastatic ACC of the right kidney after a 3-year postsurgery period of the primary submandibular gland.[8]

Chen et al. reported a case of development of renal metastasis after 8-year interval period of primary maxillary ACC treatment and also reviewed total of 15 cases of ACC originated from different locations and metastasized to renal between 1984 and 2014. They found average interval between occurrence of primary tumor surgery and development of renal metastasis was 9.8 years which represent indolent growth pattern and high potential of late metastases.[9]

In this case, we have found sinonasal ACC with the early occurrence of renal metastasis within a year of initial presentation. All reported cases have not mentioned the morphological status of primary site lesion in terms of size, extent, skull base involvement, positive margin, perineural spread, and grade of lesion favoring early metastasis. In our case, the primary disease is locally advanced, aggressive, large in size, skull base involvement, poorly differentiated tumor on the histopathological evaluation, and remained untreated since initial presentation which could be the possible reasons for the early occurrence of metastasis. It needs further extensive clinical research and study.

Conclusion

Hence, in conclusion, there is an important role of whole-body imaging, that is, FDG PET-CT scan in ACC to delineate locally advanced disease and distant systemic metastasis. With the help of side-by-side analysis of MRI or dedicated PET-MRI scan, evaluation of perineural metastatic spread may helpful in prognostication, and thus change the staging and disease management.

As per our knowledge, this is the third case report of FDG PET-CT scan revealing renal metastatic ACC.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.