Pancreatic Adenocarcinoma: This is the most common type of pancreatic cancer, often presenting as a hypo-enhancing mass on CT scans. The location at the pancreatic body/tail junction and the presence of severe stenosis of the splenic artery (likely referred to as "spinal artery" in error) adjacent to the mass are consistent with this diagnosis. The mild elevation in liver enzymes and normal lipase levels do not strongly argue against this diagnosis, as pancreatic adenocarcinoma can present with a variety of laboratory findings.

Pancreatic Neuroendocrine Tumor (PNET): Although less common than adenocarcinoma, PNETs can also present as hypo-enhancing masses, especially if they are non-functioning. The location and vascular involvement could fit with this diagnosis, though typically, PNETs are more vascular and might show different enhancement patterns.
Pancreatic Lymphoma: This is a less common pancreatic tumor that can present as a hypo-enhancing mass. It might be considered, especially if there are systemic symptoms or other signs of lymphoma, though the provided information does not strongly suggest this.

Pancreatic Metastasis: Metastases to the pancreas from other primary cancers (e.g., lung, breast, renal cell carcinoma) can present as hypo-enhancing masses. Given the potential for significant impact on treatment and prognosis, considering metastasis is crucial, even if the primary presentation might seem atypical.
Intraductal Papillary Mucinous Neoplasm (IPMN) with Malignant Degeneration: While IPMNs are typically characterized by their connection to the pancreatic ductal system and may show different imaging characteristics, a solid component within an IPMN could mimic a hypo-enhancing mass. The severe stenosis of the adjacent artery is less typical but could be seen in cases of malignant degeneration.

Solid Pseudopapillary Neoplasm (SPN): A rare pancreatic tumor that can present as a well-circumscribed mass, sometimes with degenerative changes that might appear hypo-enhancing. It is more common in young women and typically has a better prognosis than adenocarcinoma.
Pancreatic Sarcoma: Extremely rare, pancreatic sarcomas can present as masses but are much less common than adenocarcinoma or other diagnoses listed here. They might show a variety of imaging characteristics, including hypo-enhancement, depending on the specific type of sarcoma.