Introduction:
Choledochoduodenal fistulas (CDF) are an uncommon and complex clinical
entity, characterised by an abnormal communication between the common
bile duct and duodenum. These fistulas may arise from a number of
underlying conditions, including chronic inflammatory pathologies,
peptic ulcer disease, malignancies, and trauma (1). Whilst there are
documented cases of CDF arising from diffuse large B-cell lymphoma
(DLBCL) of the duodenum following initiation of systemic chemotherapy,
their occurrence secondary to non-Hodgkin’s lymphoma of the pancreas is
an exceedingly rare phenomenon, with no previously documented cases in
the literature (2).
Despite the myriad of causes of CDF, their occurrence secondary to
non-Hodgkin’s lymphoma of the pancreas is exceptionally rare.
Non-Hodgkin’s lymphomas encompass a diverse group of haematological
malignancies characterised by the histological absence of Reed-Sternberg
cells. Most originate from B-cell lines, with DLBCL being the most
prevalent subtype (3). Since the 1970s, the incidence of non-Hodgkin’s
lymphoma has doubled, affecting one in ten-thousand individuals. While
75% of patients present with nodal disease, 25% may exhibit
extra-nodal disease, involving the skin, oropharynx, gastrointestinal
tract, bone, central nervous system and lungs. The pancreas, however,
remains an exceptionally uncommon site of primary lymphoma formation,
accounting for only 1% of extranodal lymphomas and 0.5% of all
pancreatic tumours (4).
High grade lymphomas such as DLBCL are typically more aggressive than
their low grade counterparts, but are often more amenable to curative
treatment. They are characterised by rapidly enlarging lymphadenopathy
and systemic symptoms such as fever, nocturnal diaphoresis and weight
loss. Conversely, pancreatic lymphomas tend to display a more insidious
onset with non-specific symptoms, hence complicating the diagnostic
process (3). The formation of CDF in this context represents an
extremely rare and late-stage manifestation, underscoring the intricate
interplay between lymphomatous infiltration, local tissue destruction
and subsequent fistula formation. These fistulas demonstrate the
potential for serious complications, including biliary obstruction,
cholangitis and sepsis.
This case report elucidates the clinical course of a patient with CDF
arising secondary to pancreatic DLBCL, as well as the diagnostic and
managemental challenges encountered. The rarity of this complication of
pancreatic DLBCL is underscored by the apparent absence of documented
cases in the existing literature. Moreover, this report seeks to
contribute to the growing body of knowledge surrounding the complex
interplay between lymphoproliferative disorders and gastrointestinal
complications, emphasising the importance of clinical vigilance in
patients presenting with atypical symptoms.