Intestinal-type sinonasal adenocarcinoma in a patient without previous exposure to dust

Clinical History

A 64-year-old male patient was referred to our hospital with a nasal obstruction. General examination of the nose revealed no abnormalities. The patient underwent an ENT examination with fibreoptic endoscopy, which showed a soft tissue-like mass occupying the maxillary sinus without bleeding. There was no history of occupational exposure to dust.

Imaging Findings

An MRI study with and without contrast administration revealed a mass-like structure in the right nasal cavity and ipsilateral ethmoid obstructing the right-sided paranasal sinuses. The tumour extended into the nasopharynx. The tumour showed low signal intensity on T1-weighted images (Fig. 1) and inhomogeneous high signal intensity on T2-weighted images (Fig. 2). After administration of a gadolinium-based contrast agent, the lesion showed enhancement. Areas of intratumoural signal heterogeneity were secondary to haemorrhage and necrosis. On postcontrast sequence, there was solid tumour enhancement, with nonenhancement of necrotic lesional components (Fig. 3).
The tumour was resected and histopathologic examination revealed invasive adenocarcinoma of the intestinal type (Fig. 4). Imaging of the colon and a CT examination of the abdomen showed no evidence of primary malignancy. The patient underwent radiation treatment.

Discussion

Intestinal type sinonasal adenocarcinoma (ITAC) is a rare malignancy of the nasal cavity and paranasal sinuses. Its association with lengthy occupational exposure to dust has been well documented [1], but sporadic cases have also been reported.
The incidence is 1% of all cancers, and 1.4% of cancers typical of the region. The overall mortality rate is about 53% [2]. It is closely related to occupational exposures to substances such as wood and leather dust, solvents, metals and formaldehyde [3].The nasal cavity and paranasal sinuses cavity are the most common locations. Reported sites for the origin of ITACs are as follows: ethmoid sinuses, 40%; nasal cavity, 28%; maxillary antrum, 23%; and indeterminate, 9%. The initial symptoms are usually nonspecific with significant symptomatologic overlap with sinus inflammatory disease. Patients may present with nasal obstruction, epistaxis, rhinorrhoea, mass in the cheek, and exophthalmos. Less common are symptoms related to facial nerve involvement. ITACs occur between the sixth and seventh decade of life after a latency of about 40 years. Male preponderance has been noted (M/F ratio of 2.2: 1) [4].Tumours tend to be very locally aggressive. Metastatic adenocarcinomas from the gastrointestinal tract must be excluded by appropriate imaging or endoscopic studies. Immunohistochemical staining for carcinoembryonic antigen (CEA) has been proposed as a method of differentiating metastatic colonic adenocarcinomas from primary ITAC, with strongly positive staining favouring metastatic disease [5-7]. Sinonasal ITAC is characterized by one or more local recurrences in more than 50% of patients. Regional lymph nodes and distant metastases are less commonly seen, occurring in 8% and 13% of patients, respectively. The most frequent sites of metastases are the lungs, liver, and bones. CT and MRI play complementary roles in the assessment and staging of sinonasal malignancies. CT has high spatial resolution, it depicts osseous involvement and erosion, providing details on the aggressiveness of the lesion, as well as affording surgical mapping. Magnetic resonance imaging (MRI) helps to differentiate between inflammatory disease and sinonasal masses and also illustrates the tumour boundaries and extent.
MRI is an important evaluation tool to delineate the extent of the tumour, including involvement of adjacent structures, and to evaluate for perineural spread, all of which affect the prognosis and help determine treatment options [8]. In this type of tumour the particular finding in MRI is hyperintensity on T2 and slight enhancement, resembling unilateral polyposis. Imaging usually cannot distinguish between different histologic types; definitive diagnosis requires histological evaluation. The treatment of choice is usually both surgery and radiation.

Differential Diagnosis List

Final Diagnosis

The histopatological diagnosis was adenocarcinoma of intestinal type.

URL:	https://www.eurorad.org/case/12165
DOI:	10.1594/EURORAD/CASE.12165
ISSN:	1563-4086