A rare case of a pancreatic mass due to accessory spleen; when EUS-FNA is not enough

Ultrasonographic and colour Doppler features of intrapancreatic splenic tissue in a cat

Case summary

A 2-year-old female neutered domestic longhair cat was referred for a 3-day history of lethargy and anorexia. Physical examination documented abdominal distension and pain, which, alongside marked electrolyte imbalances on blood biochemistry, was highly suspicious for a gastrointestinal obstruction. This was confirmed on diagnostic imaging, with abdominal ultrasonography also identifying an incidental, well-defined small lobular hypoechoic nodule adjacent to the tail of the spleen, with high vascularity on Doppler interrogation. This was identified as a focal nodule at the tip of the left limb of the pancreas at surgery, and resected via partial pancreatectomy. Histopathological examination confirmed intrapancreatic splenic tissue.

Relevance and novel information

This case report presents the first available ultrasonographic description and images of intrapancreatic splenic tissue in a cat. It is thought to be a benign lesion of low clinical significance and therefore defining its imaging characteristics may allow for improvement in diagnostic suspicion without resorting to excisional surgery.

Intrapancreatic accessory spleen false positive to 68Ga-Dotatoc: case report and literature review

Background

Intrapancreatic accessory spleen (IPAS) is an uncommon finding of pancreatic mass. Differential diagnosis with pancreatic tumor, especially with non-functional neuroendocrine tumor (NF-NET), may be very hard and sometimes it entails unnecessary surgery. A combination of CT scan, MRI, and nuclear medicine can confirm the diagnosis of IPAS. 68-Ga-Dotatoc PET/CT is the gold standard in NET diagnosis and it can allow to distinguish between IPAS and NET.

Case presentation

A 69-year-old man was admitted to our hospital for an incidental nodule in the tail of the pancreas with focal uptake of 68-Ga-dotatate at PET/CT. NET was suspected and open distal splenopancreatectomy was performed. Pathologic examination revealed an IPAS.

Conclusion

This is the second IPAS case in which a positive 68Ga-Dotatoc uptake led to a false diagnosis of pancreatic NET. Here is a proposal of a literature review.

Intrapancreatic accessory spleen: a diagnostic dilemma

BACKGROUND

As intrapancreatic accessory spleen (IPAS) is rarely encountered during clinical practice, the aim of this review was to summarize the epidemiologic features, the diagnosis and treatment of IPAS.

METHODS

MEDLINE and EMBASE were searched for articles reporting on IPAS. Categorical variables were reported as frequency and percentage. Continuous variables were reported as median (range).

RESULTS

A total of 105 patients were included, of which 73% were detected incidentally. The male/female ratio was 1.23. The size of IPAS in patients who had previously undergone splenectomy was larger than that of patients without prior splenectomy (2.5 cm vs 1.5 cm; p = 0.020). No preoperative examination was able to make a definite diagnosis for all IPASs. More than half of the patients (55%) received surgical treatment, most of which (87%) were suspected as pancreatic neuroendocrine tumors (p-net) preoperatively.

CONCLUSIONS

Although rare, IPAS should be considered in the differential of patients with suspected incidental p-net, especially if there has been a past history of splenectomy. Preoperative diagnosis is important as unnecessary surgery can be avoided. As it is difficult to make a definite diagnosis of IPAS by one single examination, multiple techniques may be required.

Intrapancreatic Accessory Spleen: A Diagnosis Not to Forget!

A 69-year-old male patient was incidentally diagnosed with a 5-mm lesion in the pancreatic tail by endoscopic ultrasound (EUS). After contrast-enhanced EUS and EUS-elastography, all imaging features were highly suggestive of a benign pancreatic solid lesion such as an intrapancreatic accessory spleen (IPAS) or a benign neuroendocrine tumor. Interposition of the splenic artery precluded EUS-guided fine-needle aspiration (FNA). When an asymptomatic pancreatic mass is detected, IPAS diagnosis should be considered, and, if EUS-FNA is infeasible, contrast-enhanced EUS and EUS-elastography are useful tools to differentiate a pancreatic benign lesion as IPAS from a malignancy, with avoidance of unnecessary surgery.

Large platelet aggregates in endoscopic ultrasound-guided fine-needle aspiration of the pancreas and peripancreatic region: a clue for the diagnosis of intrapancreatic or accessory spleen

Intrapancreatic and intraabdominal accessory spleens (IPIASs) are rarely encountered in endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) biopsies. However, as incidentally discovered IPIAS can mimic a benign or malignant pancreatic neoplasm on imaging studies, a definitive diagnosis made by EUS-FNA can avert an unnecessary surgical intervention or additional radiologic follow-up. We report five cases of intrapancreatic splenules and one case of accessory spleen (AS) in which a definitive diagnosis was made on EUS-FNA. Previously recognized FNA cytomorphologic features of splenic tissue, including ASs and splenosis, are endothelial cells and polymorphous lymphocytes admixed with neutrophils, eosinophils, plasma cells, histiocytes, and lymphoglandular bodies. We describe the additional finding of abundant large platelet aggregates as another distinguishing feature of splenic tissue on FNA. In all six cases, large platelet aggregates were identified along with polymorphous lymphoid cells, lymphoglandular bodies, loose aggregates of endothelial cells and scattered or aggregated bland spindle cells. A review of 10 consecutive cases of EUS-FNA-sampled benign intraabdominal lymph nodes showed that the presence of large platelet aggregates, three-dimensional aggregates of lymphoid cells and of bland slender spindle cells and the absence of follicular germinal cell components (tingible body macrophages and lymphohistiocytic aggregates) are useful in differentiating IPIASs from reactive lymph nodes. Immunoperoxidase stains were useful to confirm a suspected IPIASs by showing CD31-positive acellular flocculent material, consistent with large platelet aggregates and a rich CD8-positive endothelial cell network between CD45-positive lymphoid cells and CD68-positive histiocytes in all six cases.