Malignant biliary obstruction due to metastatic non-hepato-pancreato-biliary cancer

Table 1 Computed tomography findings of pancreatic metastases

						Primary Malignancy							Characteristics
Ref.	Year	Cases	Renal	Lung	Breast	Stomach	Colon	Sarcoma	Melanoma	Ovary	Thyroid	Other	Solitary mass	Multiple nodules	Diffuse involvement
Ferrozzi et al[14]	1997	20	2	6	3	3	1		2	2	1		11	2	7
Klein et al [15]	1998	66	20	15	8	4		5	4	2	1	7	52	11	3
Tsitouridis et al [16]	2009	11	1	7	3								7	3	1
Angelleli et al [17]	2012	17	8	4	3			2					7	9	1
Shi et al [18]	2015	18	3	7		5 (stomach+colon)		2				1	12	6
Choi et al [19]	2015	36	17	2		5	7	1	1	1		2	29	7
Galia et al [20]	2018	24	6	8	2			1			4	3	9	13	2
Total		192	57	49	19	12	8	11	7	5	6	13	127	51	14
% of total			30%	26%	10%	7%	5%	6%	4%	3%	3%	7%	66%	27%	7%

Table 2 Relative frequency of pancreatic metastases by modality/procedure

Modality/procedure	Total cases	Renal	Lung	Breast	Stomach	Colon	Sarcoma	Melanoma	Ovary	Thyroid	Esophagus	Lymphoma	Other
CT	192	30%	26%	10%	7%	5%	6%	4%	3%	3%	0%	0%	7%
ERCP	307	1%	3%	4%	27%	38%	0%	2%	2%	0%	2%	1%	20%
EUS-FNA	515	40%	20%	6%	2%	9%	3%	10%	3%	1%	2%	0%	3%
Surgery	399	63%	3%	3%	3%	6%	7%	4%	5%	0%	0%	0%	6%
Autopsy	184	3%	28%	4%	22%	1%	2%	1%	2%	1%	0%	5%	31%
Weighted average1	1597	33%	14%	5%	10%	12%	4%	5%	3%	1%	1%	1%	11%

¹Excludes duplicate data from the same institution during the same period using the same modality. Does not consider possible data duplication across studies of different modalities.

CT: Computed tomography; ERCP: Endoscopic retrograde cholangiopancreatography; EUS-FNA: Endoscopic ultrasound-guided fine-needle aspiration.

Table 3 Characteristics of malignant biliary obstruction caused by various primary malignancies

	Unique characteristics/diagnostic clues	Major causes of malignant biliary obstruction
Renal cell carcinoma	Enhancing lesion on imaging. Most pancreatic metastases resectable and associated with a good prognosis. Can arise up to 32 years after diagnosis of primary tumor	Pancreatic metastasis (biliary obstruction rare)
Lung cancer	Most reported in small cell lung cancer. Possible primary small cell biliary cancer	Pancreatic metastasis
Gastric cancer	Most cases present after surgery for Borrmann 3 antral lesions. Possible need for double stenting due to gastric outlet obstruction	Lymph nodes, liver metastasis, direct invasion
Colorectal cancer	Intraductal growth can mimic bile duct cancer	Liver metastasis, lymph nodes
Breast cancer	Most reported in invasive lobular carcinoma. Possible duodenal obstructionCan arise up to 32 years after diagnosis of primary tumor	Lymph nodes, pancreatic metastasis
Melanoma	Possible pancreato-biliary primary	Pancreatic metastasis
Lymphoma	More common in non-Hodgkin's lymphoma. Possible pancreato-biliary primary	Lymph nodes
Sarcoma	Possible pancreato-biliary primary	Pancreatic metastasis