Mesenteric Hemolymphangioma: A Case Report and Literature Review.

Introduction
Lymphangioma is an extremely rare clinical disease that predominantly occurs in children [1]. As a subtype of lymphangioma, hemolymphangiomas are even less frequently reported in the literature [2]. Documented cases have been identified primarily in the head and neck region [3], small intestine [4], pancreas [5–7], stomach [8], posterior mediastinum [9], and retroperitoneum [10]. Mesenteric involvement is notably rare. A search of the PubMed and Medline databases using the keywords “hemolymphangioma”, “hemangiolymphangioma”, and “mesentery” revealed 4 adult patients with mesenteric hemolymphangioma, located in the small intestine mesentery and transverse mesocolon [11–13]. In this report, we present a case of hemolymphangioma of the mesenteric root in a pediatric patient, discuss the clinical characteristics and treatment process, and review the literature, to provide insights for future clinical practice.

Case Report
A 15-year-old boy presented with recurrent abdominal pain for more than 2 years. The patient had no history of abdominal trauma or prior surgery. Due to the clinical suspicion of a retroperitoneal mass, CT was performed directly, without prior ultrasound. Preoperative CT revealed a retroperitoneal mass located anterior and lateral to the duodenum and inferior to the pancreatic head (Figure 1). Laboratory tests, including complete blood count, biochemistry, coagulation profile, and tumor markers, were unremarkable (Table 1).
During surgical exploration, intraoperative findings included dilated lymphatic vessels, with chylous accumulation in parts of the small intestine mesentery. A multilocular cystic mass, approximately 12×6× cm in size, was identified in the right retroperitoneum, posterior to the ascending colon mesentery and at the root of the mesentery. The mass, with visible vascularization on its surface, was adherent to the lower edge of the duodenum and pancreatic head and extended toward the mesenteric root (Figure 2). The chylous leakage was attributed to localized lymphatic obstruction by the tumor. The surgical procedure involved an extended Kocher incision, followed by mobilization of the right hemicolon, mesentery, and pancreaticoduodenal region. Dissection was carefully performed around the tumor–mesenteric interface. Near the mesenteric root, the lymphatic connection between the cystic mass and the mesenteric root was ligated and transected. The cyst was completely separated from the pancreas and duodenum, which are closely associated with the tumor. The mass was meticulously excised via electrocautery, with ligation and division of the arterial supply originating from the pancreatic head. After complete tumor resection, the abdomen was closed. A drainage tube was placed during the operation, and no chylous leakage appeared after the operation. The drainage tube was removed 5 days after surgery.
On the pathology report, the diagnosis was hemolymphangioma, which was primarily composed of lymphangiomatous components with vascular elements. The tumor measured 12×7.5×3 cm. The immunohistochemistry results were as follows: CKpan (−), CK5/6 (−), calretinin (−), MC (+), D2–40 (+), CD31 (+), CD34 (+), SMA (+), and Ki67 (1%+) (Figure 3). These findings are consistent with features of hemolymphangioma previously described in the soft tissue pathology literature [11–13].
A follow-up CT scan conducted 2 weeks postoperatively revealed no evidence of complications or recurrence (Figure 4).

Discussion
Hemolymphangiomas occur primarily in childhood, with an incidence rate of approximately 1.2 to 2.8 in 1000 [14], and researchers suggest that hemolymphangioma is a congenital malformation that often presents with subtle clinical symptoms. This condition is considered a congenital malformation resulting from failed connection of primitive lymphatic sacs to the venous system, leading to sequestered lymphatic tissue that proliferates abnormally. Rare acquired forms can follow trauma or inflammation. This lesion is a benign lesion characterized by lymphatic vessel dilation, erythrocyte extravasation, hemosiderin deposition, and fibrosis within the tumor [15].
Reports of hemolymphangiomas as a mesenteric mass are rare. A literature search revealed only 4 cases (Table 2). All patients were adults, and underwent surgical resection, and none experienced recurrence within 4 months postoperatively.
This case of hemolymphangioma had a prolonged disease course, spanning 2 years from the onset of abdominal pain to surgical intervention. By the time of discovery, the tumor had grown to a length of 10.3 cm. Preoperative CT revealed a spindle-shaped mass with relatively uniform density and localized enhancement, suggesting the presence of vascular components. Intraoperatively, the tumor was found at the root of the mesentery, causing lymphatic vessel dilation in the local small intestine drainage area, along with chylous fluid leakage. The mass was adjacent to the pancreas and duodenum but did not invade these structures, which is consistent with the previously reported characteristic of low invasiveness [11,12]. Additionally, the tumor was encapsulated, soft in texture, and had some degree of mobility, which are not typical features of malignant tumors. Histopathologically, the tumor consisted of a mixture of lymphatic and blood vessels with multiple cystic spaces. The immunohistochemistry results were positive for D2–40, CD31, and CD34, leading to the final diagnosis of hemolymphangioma.
Hemolymphangiomas generally have a good prognosis following complete surgical resection [16]. Li X et al reported a case of gastric hemolymphangioma treated with resection, with no recurrence after 18 months of follow-up [13]. Li Y et al found no complications or recurrences in a patient with a pancreatic hemolymphangioma 2 months after surgical removal [17]. Du et al reported no recurrence or metastasis in 2 cases of small intestinal mesenteric hemolymphangioma after complete resection and 4 months of follow-up [11]. Furthermore, a literature search of PubMed and Medline revealed no reports of recurrence after hemolymphangioma resection. In the present case, the patient underwent complete tumor resection, with no recurrence observed during follow-up.
In addition to surgical treatment, other therapies for hemolymphangioma include aspiration and drainage, cryotherapy, injection of sclerotic agents, laser therapy, and radiotherapy. On the basis of previously published literature and clinical experience, we believe that surgical resection is the treatment of choice, especially for larger tumors located in the mesentery that cause compression symptoms or other consequences, such as segmental lymphatic vessel dilation. If lymphatic decompression is not performed in a timely manner, it can lead to chylous accumulation, chylous fistula, or ascites. In this case, after tumor resection, the dilated lymphatic vessels shortened in length and decreased in tension, which may have been related to the restoration of small intestinal lymphatic drainage after surgical decompression. According to the literature, the recurrence rate of hemolymphangiomas is 10% to 27% following complete excision of the lesion, whereas partial resection results in a recurrence rate of 50% to 100% [17,18]. Therefore, complete resection should be the goal, even if it requires combined organ resection, including challenging procedures, such as pancreaticoduodenectomy, to ensure thorough excision and reduce the risk of postoperative recurrence and the need for reoperation.

Conclusions
Hemolymphangioma is a rare clinical condition with diverse locations and presentations, often with subtle symptoms and nonspecific CT findings, making clinical diagnosis challenging. A definitive diagnosis can be made only by identifying the vascular and lymphatic components in pathological sections and the specific expression of immunohistochemical markers, such as D2–40, CD31, and CD34, in conjunction with clinical presentation and imaging findings. By sharing this case of mesenteric root hemolymphangioma, we aim to describe its location and clinical characteristics to provide a reference for clinicians in future work.