Left sided discomfort and a palpable abdominal mass.

The patient is a 63 year old Iranian woman with a 3 week history of left- sided discomfort. She noticed this when traveling. She subsequently returned to the US for evaluation. She has never had pancreatitis or jaundice. Her weight has been stable. She has no left-sided abdominal trauma, and no past history of malignancy.

Hypertension and hypercholesterolemia.

No previous surgical procedures.

Sectral, Dyazide, Lipitor, and Teveten.

She is a non-smoker and does not drink alcohol. She is married with two children and two grandchildren.

No history of malignancy.

Codeine (rash).

General: Healthy, non-obese woman who appears younger than her stated age of 63. No evidence of cachexia.
Vital Signs: Pulse 60, irregular, BP 110/70, RR 16, T 37.0
HEENT: Normal
Neck: Normal, no lymphadenopathy
Cardiac: Normal
Chest: Normal
Abdomen: There is a palpable left upper quadrant mass, no periumbilical lymphadenopathy.
GI: Stool hemeoccult negative. No masses in rectum.
Skin: Normal.
Neuro: Normal

Na 141, K 4.4, Cl 102, BUN 19, Cr 0.9, Glu 78, Ca 9.7
Total Bili 0.4, Direct Bili 0.1 AST 22, ALT 16, Alk Phos 67, Tot Prot 7.6, Alb 4.4
Amylase 59, Lipase 31
WBC 6060, Hct 41%, Hgb 13.6, MCV 90.4, Plt 298,000
APTT 29.4, Ratio APTT 1.0, PT 10.7, INR 1.0
CEA 1.0
Blood type B positive

Sinus bradycardia with incomplete right bundle branch block and possible left atrial abnormality.

There is an approximately 9 cm cystic mass extending from the tail of the pancreas into the mesentery of the proximal jejunum, pushing against the splenic vein. The mass appears to be adjacent to the left kidney, close to the spleen, and also close to back wall of the stomach (Images 1-3).

What is the differential diagnosis of a cystic mass in this location?
What is the next indicated procedure?