Teaching Case

A 66-year-old female with a history of acute myeloid leukaemia (AML) treated with a bone marrow transplant presented with progressive generalized weakness, epigastric abdominal pain radiating to her back, and jaundice. Physical examination showed icteric sclera and mild, generalized abdominal tenderness.

CT imaging revealed the presence of two pancreatic nodules located in the head and body. The nodules showed peripheral enhancement and central hypoenhancement suggestive of necrosis. MR imaging also showed the same nodules, which appeared hyperintense in T2-weighted sequences and hypointense in T1-weighted sequences. The lesions showed restricted diffusion and also displayed peripheral enhancement and central hypoenhancement in the post-contrast sequences. CT and MRI didn’t show evidence of main pancreatic duct or biliary tree dilation.

Background

Pancreatic myeloid sarcoma is a rare extramedullary manifestation of acute myeloid leukaemia (AML). It is characterized by the presence of myeloid blasts infiltrating the pancreas without involving the bone marrow, leading to organ dysfunction and the presentation of clinical symptoms. [1]

Clinical Perspective

The typical clinical presentation of pancreatic myeloid sarcoma is non-specific and includes abdominal pain, nausea, vomiting, and weight loss. Imaging is necessary to differentiate pancreatic myeloid sarcoma from other pancreatic masses, as it can mimic pancreatic adenocarcinoma. It is essential to convey to the requesting physician that pancreatic myeloid sarcoma should be considered in the differential diagnosis of pancreatic masses, especially in patients with a history of AML [2].

Imaging Perspective

Diagnostic imaging modalities, such as computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET), can provide diagnostic pearls and key findings for pancreatic myeloid sarcoma [3]. CT and MRI can show an enhancing mass with variable degrees of necrosis and cystic changes. PET can show increased metabolic activity within the mass. However, the definitive diagnosis of pancreatic myeloid sarcoma requires a biopsy [4].

Outcome

Treatment options for pancreatic myeloid sarcoma include systemic chemotherapy, radiation therapy, and surgery [3]. The prognosis for pancreatic myeloid sarcoma is poor, with a median survival of less than one year [2]. The impact of imaging on therapy planning involves determining the extent of the disease and guiding the selection of appropriate treatment modalities. This patient was treated with reinduction therapy with Mitoxantrone + Cytarabine, resulting in the reduction of the lesion size and stability so far.

Take Home Message / Teaching Points

Pancreatic myeloid sarcoma is a rare manifestation of AML that can mimic pancreatic adenocarcinoma on imaging studies. Diagnostic imaging modalities can aid in the diagnosis of pancreatic myeloid sarcoma, but definitive diagnosis requires a biopsy. It is important to consider pancreatic myeloid sarcoma in the differential diagnosis of pancreatic masses, especially in patients with a history of AML. Treatment options for pancreatic myeloid sarcoma include systemic chemotherapy, radiation therapy, and surgery, with a poor prognosis for the disease.