Teaching Case

A 15-year-old female with Burundi’s origin presented with upper abdominal pain of six months duration, without weight-loss.
Upper abdominal ultrasound was performed, followed by MR.
On the suspicion of a pancreatic tumour the patient underwent EUS-FNA. Cytological examination revealed the presence of necrosis, Langhans’ giant cells, lymphocytes and macrophages organised in granulomas.

Axial ultrasound view of the upper abdomen showed a hypoechogenic mass in the pancreatic head.
T2-weighted TSE MR images showed a predominately hyperintense heterogeneous mass in the pancreatic head. Coronal T2-weighted MRCP showed a long stenotic segment of the distal common bile duct (CBD) resulting in moderate intra-hepatic biliary dilatation. There was a mild stenosis of the main pancreatic duct (MPD) in the pancreatic head, without significant upstream dilatation.
T1-weighted GE MR images before and after gadolinium administration demonstrates delayed heterogeneous enhancement of the lesion. No signs of vascular encasement.
There was peripheral ring enhancement of the lymph nodes with hypointense necrotic centre.
Axial diffusion-weighted (b=1000s/mm2) and fusion images showed intense diffusion restriction of the lesion and peripancreatic lymph nodes.
Chest X-ray was normal and there were no other abnormalities. There was no evidence to suggest disseminated or pulmonary tuberculosis.
Two months into anti-tubercular treatment, there was significant reduction of the pancreatic lesion.

The pancreas is considered to be markedly resistant to tuberculosis, so pancreatic tuberculosis is considered to be uncommon [1]. It usually occurs as a complication of miliary tuberculosis and immunodeficiency, with isolated involvement of the pancreas being exceedingly rare [2]. It usually affects young adults with a slight predominance of female over male and higher incidences have been observed in endemic areas and in the immunocompromised population. Recent globalisation trends and widespread migration has seen cases diagnosed in areas where tuberculosis is not prevalent [3].
Focal tuberculous involvement of the pancreas has been reported to occur most frequently in the pancreatic head, followed by the pancreatic body and tail. Diffuse pancreatic involvement is exceedingly rare [2].
Imaging features are nonspecific and may resemble those of inflammatory or neoplastic lesions of the pancreas. The MRI finding of focal pancreatic tuberculosis is a sharply delineated mass with heterogeneous enhancement, occasionally with a cystic component. The concomitant presence of enlarged, centrally necrotic locoregional lymph nodes is an important ancillary finding, not always found [2].
The finding of caseating granulomatous inflammation is diagnostic of pancreatic tuberculosis. Acid-fast bacilli may be seen in some cases. In resected specimens a polymerase chain reaction assay, which reveals Mycobacterium tuberculosis DNA, is a highly specific test [1].
The main differential diagnosis, namely at this age, is lymphoma, that can present as diffusely enlarged pancreas as well as a focal mass, as in our case. Retroperitoneal adenopathy is usually present [4].
Autoimmune pancreatitis, as lymphoma, presents more frequently as diffuse enlarged pancreas, with no significant enlargement of peripancreatic lymph nodes. Nonetheless it can occasionally present as a focal mass. Increases of serum IgG4 and prompt response to corticoid therapy are the ancillary diagnostic features [1].
Pancreatoblastoma is a exceedingly rare pancreatic tumour of the childhood, more frequent in males. It usually presents as a large heterogenous mass. Invasion of adjacent organs, vascular encasement and distant metastases may occur [4].
Solid-pseudopapillary tumour is a unique tumour of low malignant potential most commonly affecting females of reproductive age. Its internal architecture varies from a solid mass to a thick-walled cyst, with most tumours appearing as a mixture of solid and cystic elements [4].