A. There is an heterogenous enhancing mass in the right chest wall with intrathoracic extension and involvement of the intercostal muscles and pleural space. There is a large right pleural effusion and collapse of the right middle and lower lobes. There is mediastinal shift to the left.

B, C. The right chest wall mass is markedly hypermetabolic (SUV_max of 15.1).

D, E. The intercostal muscle involvement is well demonstrated.

F. There are numerous other sites of involvement suggestive of metastatic disease. These include: Hypermetabolic (SUV_max of 12.3) pleural mass in the right upper posterior hemithorax; hypermetabolic (SUV_max of 7.5) mass in the mediastinal pleura adjacent to the collapsed right lower lobe; hypermetabolic lymph nodes (SUV_max 2.2- 3.8) in the mediastinal and retrocrural regions; hypermetabolic mass (SUV_max of 7.5) in the right anterior nasal cavity adjacent to the inferior nasal concha that may represent nasal lymphoma; hypermetabolic lymph nodes in the neck (SUV_max 2.3- 15.5); hypermetabolic lesions in the liver (SUV_max 3.8- 12.3); hypermetabolic, enlarged left adrenal gland (SUV_max of 3.8); hypermetabolic (SUV_max of 5.1) soft tissue nodule posterior to the upper right kidney; moderate ascites; multiple hypermetabolic bone lesions (SUV_max 2.7- 7.8).

The differential diagnosis on PET-CT includes: mesothelioma, malignant mesenchymal tumours such as rhabdomyosarcoma; and rarely extensive pleural metastasis from lung primary.

Extranodal NK/ T-cell lymphoma, nasal type (ENKTCL) is a distinct, rare, clinico-pathologic entity associated with Epstein-Barr virus (EBV). It most commonly arises in the nasal cavity, but can also involve the face, skin, soft tissues, upper respiratory tract, and gastrointestinal tract. ENKTCL arises in all geographic locations of the world, but is predominant in South-East Asia, Mesoamerica and South America.

Viable NK lymphoma is intensely hypermetabolic, with PET-CT most sensitive for disease detection in the nasopharynx, and to a lesser extent in extranasal sites such as cutaneous lesions and bone marrow involvement. PET-CT is helpful to assess disease progress and to evaluate residual disease after therapy. PET maximum standardized uptake value (SUV_max) has not been shown to correlate with clinicopathologic features or prognosis.

NK lymphoma has an extremely poor prognosis with a median survival of less than one year. Although optimal treatment has not been clearly defined, radiotherapy and high-dose chemotherapy plus stem cell transplant are considered reasonable treatment options.