Massive splenic hamartoma with bizarre stromal cells

What is new in the 5th edition of the World Health Organization classification of mature B and T/NK cell tumors and stromal neoplasms?

The classification of tumors is essential in the diagnosis and clinical management of patients with malignant neoplasms. The World Health Organization (WHO) provides a globally applicable classification scheme of neoplasms and it was updated several times. In this review, we briefly outline the cornerstones of the upcoming 5th edition of the World Health Organization Classification of Haematolymphoid Tumours on lymphoid neoplasms. As is adopted throughout the 5th edition of the WHO classification of tumors of all organ systems, entities are listed by a hierarchical system. For the first time, tumor-like lesions have been included in the classification, and modifications of nomenclature for some entities, revisions of diagnostic criteria or subtypes, deletion of certain entities, and introduction of new entities are presented along with mesenchymal lesions specific to the stroma of lymph nodes and the spleen. In addition to specific outlines on constitutional and somatic genetic changes associated with given entities, a separate chapter on germline predisposition syndromes related to hematologic neoplasms has been added.

Successful treatment of pancreatic accessory splenic hamartoma by laparoscopic spleen-preserving distal pancreatectomy: A case report

BACKGROUND

Pancreatic accessory spleen (PAS) is an uncommon congenital abnormality of the spleen. Spleen hamartoma (SH) is also rare. Moreover, hamartoma in the PAS has not been reported thus far. We report the first case here.

CASE SUMMARY

A 26-year-old male presented with a one-month history of left upper quadrant abdominal pain, and computerized tomography (CT) examination suggested a mass in the pancreas tail. The patient then attended our hospital for diagnosis and treatment. Ultrasonography, CT, and magnetic resonance imaging revealed a solid mass with cystic degeneration growing from the tail of the pancreas. The tumor marker carbohydrate antigen 19-9 (CA19-9) increased to 96.7 U/mL (normal range 0-37 U/mL). An epidermoid cyst in a PAS was considered preoperatively. However, a malignant tumor cannot be ruled out. We performed laparoscopic surgery, and two pancreatic masses were found growing from the pancreatic tail. The two masses were so closely connected that preoperative imaging examinations suggested only one mass. We carefully isolated the masses from the splenic artery and vein. A laparoscopic spleen-preserving distal pancreatectomy was successfully performed. On pathological examination, the masses were well-defined, homogeneous red-tan, 4 × 3, and 4.5 × 1.5 in size, respectively. One of them was cystically degenerated. On microscopical examination, the mass contained unorganized small slit-like vascular channels enclosing red blood cells and lined with plump endothelial cells. No area of cytologic atypia was identified. Focal lymphoid aggregates were found in the intravascular areas. White pulp or fibrosis was not observed. The final diagnosis was pancreatic accessory SH with cystic degeneration. After the operation, CA19-9 was reduced to normal. The patient recovered well, and the 34-mo follow-up period was uneventful.

CONCLUSION

Here, we report the first case of pancreatic accessory SH. A laparoscopic spleen-preserving distal pancreatectomy was successfully performed. The patient recovered well and had a good prognosis.

Splenic hamartoma with bizarre stromal cells: a case report and literature review

Background

Splenic hamartoma is a rare benign vascular proliferative lesion composed of unorganized sinusoid-like channels lined with plump or flat endothelial cells and characterized by a CD8-positive immunophenotype of the lining cells. Scattered bizarre stromal cells can be found in some splenic hamartomas. The presence of splenic hamartoma with bizarre stromal cells is extremely rare and these bizarre cells make it possible to be regarded as a malignancy. Recognition of this rare histologic variant will help to avoid diagnostic confusion and overtreatment of this benign entity.

Case presentation

We report a case of a 40-year-old man with occasional left-sided waist back pain. A splenic space-occupying lesion was detected by ultrasound and magnetic resonance imaging. Microscopically bizarre large cells were scattered throughout the splenic hamartoma. The cells exhibited atypical nuclei, scarcely visible cytoplasm, and vesicular chromatin, and they did not form expansile clusters and lacked mitotic activity. An immunohistochemical panel was performed. The bizarre cells strongly expressed vimentin, and the Ki-67 index was very low. The lesion was diagnosed as a splenic hamartoma with bizarre stromal cells.

Conclusions

To the best of our knowledge, this is the first systematic review on a splenic hamartoma with bizarre stromal cells; only six cases have been described in the literature. Proper identification is important to secure adequate treatment.