Indian Journal of Pathology and Microbiology

CASE REPORT
Year
: 2010  |  Volume : 53  |  Issue : 1  |  Page : 106--108

Serous microcystic adenoma (glycogen rich cystadenoma) of the pancreas


Sunitha Jacob, Premeeta Rawat, Ruth Prasanna Mark 
 Department of Pathology, Christian Medical College & Hospital, Ludhiana, India

Correspondence Address:
Sunitha Jacob
Department of Pathology, Christian Medical College & Hospital, Ludhiana
India

Abstract

Serous microcystic adenoma (SMCA) is a rare pancreatic tumor with a striking predilection for elderly females and a rather unique morphology. Classically, the tumor is riddled with innumerable small cysts around a stellate scar. The quintessential histological features are closely placed small cysts lined by glycogen rich cuboidal epithelium. In view of its excellent prognostic outcome, this tumor needs to be accurately diagnosed. This report documents a case of SMCA occurring in a 60-year-old female.



How to cite this article:
Jacob S, Rawat P, Mark RP. Serous microcystic adenoma (glycogen rich cystadenoma) of the pancreas.Indian J Pathol Microbiol 2010;53:106-108


How to cite this URL:
Jacob S, Rawat P, Mark RP. Serous microcystic adenoma (glycogen rich cystadenoma) of the pancreas. Indian J Pathol Microbiol [serial online] 2010 [cited 2022 Jan 23 ];53:106-108
Available from: https://www.ijpmonline.org/text.asp?2010/53/1/106/59195


Full Text

 Introduction



The classification of cystic pancreatic tumors was beset with confusion among pathologists till the landmark paper of Compagno and Oertel [1] in 1978 that defined and separated serous cystic pancreatic tumors, which are almost always benign, from mucinous tumors which are potentially or frankly malignant.

Serous microcystic cystadenoma (SMCA) of the pancreas is a rare benign tumor occurring predominantly in elderly women, composed of numerous small cysts arranged around a central, stellate scar and lined by epithelial cells with evidence of ductular differentiation. Synonyms include microcystic adenoma and glycogen-rich cystadenoma. [1] Microcystic adenoma accounts for 1-2% of all exocrine pancreatic tumors. [2]

 Case Report



A 60-year-old lady presented with colicky abdominal pain of six days duration. She was a diabetic on treatment. An ultrasound and computerized tomography (CT) scan done for suspected cholecystitis showed a well defined lobulated mass measuring 7.7x6.0x5.3cm involving the body and tail of pancreas. A clinical diagnosis of pancreatic carcinoma was made and distal pancreatectomy with splenectomy was done. No regional lymphadenopathy was noted.

Pathologic findings

Macroscopic examination showed a large, encapsulated mass measuring 8x7x4cms in the body and tail of pancreas. Cut sections of the mass revealed a 'honey comb' appearance imparted by innumerable small cysts ranging from 0.1-2.0cm in diameter [Figure 1]. Most of the cysts contained clear serous, watery or blood-tinged fluid. Also observed was a central 2x2cm irregular stellate scar.

Microscopy revealed numerous closely placed, variable sized, thin walled cysts lined by a single row of cuboidal epithelium, which in rare foci were seen forming short papillae. The epithelial lining cells possessed moderate to abundant clear cytoplasm and relatively monomorphic nuclei with inconspicuous nucleoli; no nuclear atypia or increase in mitosis was noted [Figure 2]. Staining with periodic acid-Schiff demonstrated PAS-positive, diastase-sensitive intracytoplasmic glycogen. The cyst lumina contained pale eosinophilic secretions and RBCs. The central scar was comprised of hypocellular fibrous tissue with few entrapped cysts. In most areas the tumor exhibited a well formed thick fibrous capsule. The patient was followed up regularly and found to be disease-free. She was lost to follow-up 18 months later.

 Discussion



SMCA of the pancreas is an uncommon tumor. The mean age of presentation is in the seventh decade with an age range of 34-91 years. [3] The vast majority occurs in females. [3],[4] The common presenting symptoms are abdominal pain, and/or mass, jaundice and malaise; 40% of the cases are asymptomatic and detected incidentally. [5] The location of SMCA is varied with no predilection for any part of the pancreas. The lesion is usually solitary but rarely can be multiple or diffuse. [1],[4] The size of the tumor ranges from one cm to 25cms with an average of 6-10cms. [1],[5] The tumor is encapsulated and multicystic with tiny innumerable cysts arranged around a central stellate scar. The cysts vary in size from 0.01cm to 2cm in diameter and are filled with clear or blood stained fluid. [1],[3] SMCA has a distinctive microscopic appearance with the presence of innumerable small cysts. The cysts are separated by delicate acellular connective tissue septae, contain proteinaceous fluid and are lined by a single row of cuboidal or flattened epithelial cells. The epithelial cells have central round or oval nuclei with inconspicuous nucleoli and clear or pale glycogen containing cytoplasm. [1],[4] The tumor cells are strongly positive for EMA and CK 7,8,18 and 19 and show negativity for CEA, S-100, trypsin, vimentin, synaptophysin and chromogranin. [3]

A less common variant of SMCA with a distinctly different gross morphology is the macrocystic (oligocystic) serous cystadenoma. This tumor is made up of only a few or single larger cysts between 2-8cms in diameter. The lining epithelium of the cysts is similar to that of SMCA, but unlike SMCA, this variant lacks the stellate central scar, has no sex or age predilection and occurs in children as well. However, it shares an excellent outcome with SMCA. [6]

Differential diagnosis of SMCA includes other cystic lesions of the pancreas, lymphangioma and metastatic renal cell carcinoma. Differentiation from mucinous pancreatic neoplasms is of paramount importance considering the latter's potential for malignant behavior. In mucinous cystadenomas, the lining is tall, columnar with basal nuclei and interspersed goblet cells. The surrounding stroma is dense and hyper cellular. Degenerative cystic changes in solid pseudo papillary tumors of the pancreas may cause confusion, but these cystic spaces lack an epithelial lining and moreover these tumors occur predominantly in young women. Acinar cell cystadenocarcinoma, although characterized by multicystic spongy appearance, is distinguished by lack of the central stellate scar and evidence of acinar cell differentiation. Lymphoepithelial cysts of the pancreas are unilocular, contain keratinous material and lined by squamous epithelium supported by lymphoid stroma. Lymphangioma shows relatively large cystic spaces lined by flattened cells that are glycogen and keratin negative and factor VIII Ag positive. Renal cell carcinoma is characterized by small tubular structures composed of glycogen containing cells; however, the nuclei are often irregular and with distinct nucleoli and the cells contain cytoplasmic lipid. [3]

The treatment of SMCA is mainly surgical and the prognosis is excellent. [3] However, there have been rare exceptions to the usual favorable outcome with stray reports of malignant transformation. [7] In most of these, differentiation from the benign counterpart is impossible on histologic grounds and only established by the presence of metastatic deposits. Recently, there have been reports of SMCA with the coexistence of potentially malignant pancreatic tumors like mucinous cystadenoma [8] and neuroendocrine tumors. [9]

In summary, SMCA of the pancreas is an uncommon tumor with a rather unique gross and microscopic morphology and a generally benign course. Hence it needs to be accurately diagnosed and differentiated from other malignant or potentially malignant pancreatic tumors. However, in the light of the recent findings of rare instances of malignant transformation and of co-existent potentially malignant tumors, a thorough sampling of the specimen and postoperative follow-up by regular CT surveillance is advocated.

References

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