Do not biopsy solid pseudopapillary tumors of the pancreas!

We read with interest the paper entitled “Endoscopic ultrasound-guided fine-needle aspiration for diagnosis of solid pseudopapillary tumors of the pancreas: a multicenter experience” by Jani et al., in the March issue of Endoscopy [1]. We would like to make several comments. It has been well demonstrated for many years that endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is both a useful and safe procedure for the diagnosis of solid or cystic pancreatic tumors [2] [3]. This is true for the most common solid (adenocarcinoma, endocrine) and cystic (cystadenoma) tumors. However, before performing EUS-FNA in a patient, clinicians should consider how the results of the biopsy might change the therapeutic decision, i. e. to operate or not and in some selected cases, the type of surgical procedure. In other words, which cytohistological results will change the strategy? The second question, no less important, is the safety of EUS-FNA in the setting of a rare tumor.

Solid pseudopapillary tumors of the pancreas (SPPT) usually occur in young women and their size is greater than 4 cm in the majority of the cases. In the study by Jani et al., 86 % of patients were female, the mean age was 35 years and the mean size was 42 mm. It is not specified in how many cases the diagnosis of SPPT was prompted or confirmed preoperatively on the basis of results from computed tomography (CT), magnetic resonance imaging (MRI) or EUS (without FNA). Although the radiological appearance of SPPT may vary considerably from one patient to another depending on distribution of the solid or cystic components and the importance of hemorrhagic change inside the tumor, in more than 80 % of patients the diagnosis is suggested on a radiological basis, especially when it occurs in a young woman [4] [5]. The finding of such a tumor in a young woman raises the question: which lesions might be only followed up, without surgical resection? The answer is “None!”. Therefore in these cases the performance of EUS-FNA is of no value for the patients since the vast majority, if not all of them, should undergo operation.

SPPT is considered to be a low-grade malignant tumor with an excellent long term prognosis where there is complete resection. Reports of some cases with more malignant behavior are regularly published. Some years ago, we reviewed all published cases of SPPT with distant metastasis at the time of surgical excision. Among 17 cases (including six with peritoneal carcinomatosis), a previous biopsy or tumoral trauma (i. e. drainage because of misdiagnosis with a pseudocyst, tumor opening during the intervention) was found in 11 [6]. Reports of similar cases have been published in more recent series [7]. Experienced pathologists are well aware that pressure is high inside the tumor and that the liquid component might be projected at opening the specimen, although this is not referenced. In the study by Jani et al. [1], there was no evidence of recurrence after a mean follow-up of 26 months. With a slow-growing tumor this time is too short to ensure that the procedure is safe.

In conclusion, although metastatic diffusion has never been shown after EUS-FNA in the setting of SPPT, we do think that EUS-FNA in patients with suspected SPPT not only lacks utility but may transform a low grade malignant tumor into a more aggressive one. For young women, even a very low risk for no benefit is not acceptable.

Competing interests: None

References

• 1 Jani N, Dewitt J, Eloubeidi M. et al . Endoscopic ultrasound-guided fine-needle aspiration for diagnosis of solid pseudopapillary tumors of the pancreas: a multicenter experience.  Endoscopy. 2008;  40 200-203
• 2 Hammel P, Levy P, Voitot H. et al . Preoperative cyst fluid analysis is useful for the differential diagnosis of cystic lesions of the pancreas.  Gastroenterology. 1995;  108 1230-1235
• 3 Voss M, Hammel P, Molas G. et al . Value of endoscopic ultrasound guided fine needle aspiration biopsy in the diagnosis of solid pancreatic masses.  Gut. 2000;  46 244-249
• 4 Buetow P C, Buck J L, Pantongrag-Brown L. et al . Solid and papillary epithelial neoplasm of the pancreas: imaging-pathologic correlation on 56 cases.  Radiology. 1996;  199 707-711
• 5 Machado M C, Machado M A, Bacchella T. et al . Solid pseudopapillary neoplasm of the pancreas: distinct patterns of onset, diagnosis, and prognosis for male versus female patients.  Surgery. 2008;  143 29-34
• 6 Levy P, Bougaran J, Gayet B. Diffuse peritoneal carcinosis of pseudo-papillary and solid tumor of the pancreas.  Role of abdominal injury. Gastroenterol Clin Biol. 1997;  21 789-793
• 7 Tipton S G, Smyrk T C, Sarr M G, Thompson G B. Malignant potential of solid pseudopapillary neoplasm of the pancreas.  Br J Surg. 2006;  93 733-737