Ryotaro Hashizume

Lymphangiomas are benign tumors of lymphatic origin that usually arise in the neck and axilla during childhood; intra-abdominal involvement is rare, and an omental origin in an adult is exceptional. Because imaging features are non-specific, preoperative diagnosis is difficult, and intra-cystic hemorrhage can transform an otherwise indolent lesion into a surgical emergency. We report the case of a 46-year-old man who presented with sudden right lower-quadrant abdominal pain and a soft, mobile, tender right-abdominal mass. Contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) revealed a giant (approximately 25 cm), thin-walled, multilocular cystic mass containing a hematoma, with enhancement of the cyst walls but not the internal component, and feeding vessels arising from the greater omentum. Tumor markers were normal apart from mildly elevated carbohydrate antigen (CA) 125. Because malignancy could not be excluded, open resection was performed; the tumor arose from the greater omentum without invading adjacent organs and was completely excised. Histopathology confirmed an omental lymphangioma. The acute presentation was attributable to intra-cystic hemorrhage with a focal, self-sealed rupture superimposed on an indolent lesion. Because cross-sectional imaging cannot reliably distinguish lymphangioma from other cystic lesions, an immunohistochemical panel combining lymphatic and vascular endothelial markers (D2-40, CD31) with mesothelial markers (calretinin, WT-1) was decisive in excluding a mesothelial-lined cyst and mesothelioma. Omental lymphangioma should be considered in the differential diagnosis of a giant intra-abdominal multilocular cystic mass in adults, including those presenting acutely, and complete excision is both diagnostic and curative.

INTRODUCTION: Primary splenic epidermoid cysts typically occur in young adults as unilocular lesions and are usually distinguished from lymphangiomas on histopathology, although preoperative imaging differentiation remains challenging. A multiloculated presentation in an older patient is uncommon and can be mistaken for a lymphangioma.CASE PRESENTATION: Herein, we report a 75-year-old asymptomatic woman with a multiloculated splenic cyst that was managed conservatively for approximately 10 years. CT and MRI favored a lymphangioma, and surgical resection was performed because of interval growth. Laparoscopic distal pancreatectomy with splenectomy (DP-S) was required because the cyst was firmly adherent to the pancreas. Histopathological examination revealed a 3.7 × 3.1-cm multiloculated cyst within the splenic capsule, lined by stratified squamous epithelium and associated with foamy histiocytes and cholesterol crystal clefts. Immunohistochemistry demonstrated negativity for CD31, CD34, and D2-40, and positivity for AE1/AE3, cytokeratin (CK) 5/6, and CK7, confirming a primary splenic epidermoid cyst. Negativity for calretinin and Wilms tumor 1 (WT-1) excluded a mesothelial cyst, whereas basal p63 positivity and carbohydrate antigen 19-9 expression supported the multilayered subtype. A postoperative pancreatic fistula was managed conservatively, and the patient was discharged on POD 34.CONCLUSIONS: Integrated clinicopathological assessment, rather than any single marker, is needed to distinguish a multiloculated splenic epidermoid cyst from a lymphangioma; comprehensive immunohistochemistry, including D2-40, calretinin, WT-1, and p63, is a useful adjunct. This case also shows that a benign splenic cyst may require distal pancreatectomy: when dense pancreatic adhesion is encountered intraoperatively, en bloc DP-S can become an unavoidable step toward safe and complete resection, and postoperative pancreatic fistula remains a relevant complication to anticipate.

In vitro growth curve of clone D7-R#0 DR-#5 DR after treatment with DMSO or AZD4547 (remaining results).

FGFR2 and MYC mRNA expression in clones D7 and E8.

Enhancer hijacking and FGFR2 transcript variant in clone D7-R#0.

CGH array data for clone D7-R#0.

In vitro growth curves of clones D7 and D7-R#0-5 after treatment with DMSO or AZD4547 (remaining results).

Supplementary materials and methods

FGFR2 and MYC mRNA levels in clone D7, clone D7 after 72 h of treatment with AZD4547 and clone D7-R#0-5.

Antiproliferative effect of AZD4547 on parental cells.