Nasopharyngeal lymphoma

A large fairly homogeneous mass is primarily localized to the mucosal space of the nasopharynx and oropharynx predominantly on the left extends beyond the pharynx into the parapharyngeal space on the left displacing internal carotid artery and external carotid artery posterolaterally and pushes the deep lobe of the parotid laterally.

Inferiorly the mass extends to the upper valleculae bilaterally and superiorly, it abuts the base of the skull and extends into the soft palate and across the midline. The mass is of homogeneous signal, avidly enhancing and demonstrates very low ADC values (500 x 10^-6 mm^2/s)

On the right and a similar appearing large jugulodigastric lymph node is present.

The abdominal x-ray obtained prior to MRI to exclude metallic foreign bodies (not shown) had an unusual contour and as a result and a single abdominal MRI scout and coronal T2 weighted scans were requested. These demonstrates a large lobulated retroperitoneal mass in the region of the pancreatic head.

Conclusion:

Large nasopharyngeal and oropharyngeal mass with right-sided nodal mass has signal and enhancement characteristics suggestive of an highly cellular tumor most likely lymphoma. This is supported by the presence of what appears to be a large retroperitoneal abdominal mass, which needs further assessment with CT/PET.

A PET/CT scan of the vertex to thigh was performed 55 minutes following 291 MBq of FDG infusion. Fasting blood glucose: 4.9 mmol/L. Low-dose CT was performed for attenuation correction and anatomical correlation.

Head and neck

There is a large intensely FDG-avid soft tissue mass centered in the left nasopharynx, crossing the midline to the right nasopharynx, and extends left laterally to abut the left mandible
ramus and down to the left oropharynx (SUVmax 27.2). This mass is causing obstructive congestion of the left nasal cavity and complete opacification of the left maxillary sinus. Neoplastic activity abuts the skull base without intracranial extension.

There are a few bilateral intensely FDG-avid cervical nodal metastases (up to 3cm on right; SUVmax 29.3), left supraclavicular nodal metastases and a left parotid metastatic node. A small focus of left thyroid activity (SUVmax 4.2) is either an active thyroid nodule or a left thyroid metastatic deposit.

Thorax

There are at least 5 intensely FDG-avid metastatic lymph nodes in the left internal mammary, anterior diaphragmatic (midline), and posterior mediastinal (paraesophageal) regions. No FDG-avid lung metastasis. A small nodular opacity at the right lateral lung base is very non-specific and may
be kept under CT surveillance. No breast or axillary metabolic lesion.

Abdomen and pelvis

A large intensely FDG-avid right peri-celiac mass (presumably nodal) is compressing the adjacent proximal duodenum; no gastric dilatation at present. The pancreatic head is inseparable from this peri-celiac mass. Multiple other intensely FDG-avid lymph nodes are seen in the retrocrural, gastro-hepatic, mesenteric, paraaortic, aortocaval, paracaval, right external iliac and right inguinal (2.7cm; SUVmax 31.9) regions.

Absent spleen; but in the empty splenic bed there are two soft tissue structures measuring 4cm and 3cm with mild FDG activity which are most likely accessory splenic tissue. A 2.4cm non-FDG avid right adrenal hypodense nodule could be a benign incidentaloma. No hepatic metabolic
lesion. Gallstones noted.

Conclusion

This patient has an very unusual pattern of metastatic disease that is more suggestive of lymphoma rather than nasopharyngeal primary.