Hepatic Cystic Mesenchymal Hamartoma

Introduction

Hepatic cystic mesenchymal hamartoma (MH) of the liver is a rare condition, ranking as the second most common benign liver tumor in children after infantile haemangioendothelioma. A defining characteristic of mesenchymal hamartoma (MH) of the liver is cystic hamartomatous mesenchymal proliferation.¹ Among the paediatric neoplasms, primary hepatic neoplasms represent 0.5%-2.0%.² Metastasis is the most common hepatic neoplasm in children. Primary liver neoplasms in children are mostly malignant and one-third are benign.¹

Hepatic cystic mesenchymal hamartomas (MH) have varied presentations and different pathological features. The first description of MH of the liver was given by Edmondson in 1956. Previously, it has been referred to by various names such as, cavernous lymphangiomatoid lesion, lymphangioma, and solitary bile-cell fibroadenoma.³ The pathophysiology of MH has been poorly under-stood and its management is considered controversial.^4,5 Despite variable presentations and pathological features, surgical treatment is the most recommended and successful option.

Case Presentation

A seven year old female child presented with a mass in the upper abdomen, which was noticed since one year. History of occasional nausea and vomiting since last six months was given. No history of loss of appetite or weight loss was noted. On examination, a 12 x 8 cm intraabdominal mass occupying epigastric, umbilical, right and left hypochondrium regions was noted, which moved with respiration, with restricted lateral and vertical mobility. The mass was firm in consistency, finger insanguation was not possible between left and right costal margins, and lower border was rounded with smooth surface.

Ultrasound showed large cystic lesion measuring 10.5 x 7.9 cm showing thin internal septations in the epigastric region. Posteriorly, the lesion was abutting the body of the pancreas, superiorly abutting left lobe of liver. No evidence of internal vascularity and calcification suggestive of benign cystic lesion was observed (Figure 1).

CT of abdomen and pelvis with IV contrast showed large thick-walled, peripherally enhancing hypodense cystic lesion measuring 12 x 8 x 10.7 cm with thick internal septation noted in the epigastric region and epicentred in the mesentery. The lesion was seen displacing the bowel loops bilaterally and posteriorly, was abutting the pancreatic body, superior right laterally the lesion was abutting the left lobe of liver and right laterally, the lesion was abutting the lesser curvature of stomach, suggesting benign cystic lesion, mostly a mesenteric cyst (Figures 2 and 3).

On exploration, cystic mass 12 X 11 X 8 cm arising from left lobe of liver, lobulated, occupying liver segments 1, 2, 4a, 4b of left lobe, displacing stomach, transverse colon and small bowel laterally was noted (Figure 4a). Gall bladder was normal. Cystic mass punctured revealing serosanginous content. The cystic mass was excised completely along with liver segments 2, 3, 4a of left lobe. Hemostasis was achieved and wound was closed in layers (Figure 4b). Histopathological report revealed multinodular growth of myxomatous mesenchymal stroma with intervening fibrous septa, and each nodule consisting of a bland spindle cell proliferation, suggestive of hepatic cystic mesenchymal hamartomas. Post operative period was uneventful. The child was discharged on day 3. Follow up evaluations after three months and six months showed no recurrence

Discussion

Hepatic cystic mesenchymal hamartoma is the second most common benign liver tumor in children. Edmondson was the first to use the term "mesenchymal hamartoma" of the liver, distinguishing it from other cystic and tumor-like liver lesions.³ Edmondson proposed the failure of normal development of the embryonic liver or degenerative change of an accessory lobe as the possible etiological factors. Denher et al. and Packard & Palmer^6,7 suggested developmental anomaly of the portal connective tissue in the foetal life as the responsible factor. Patients with Hepatic cystic mesenchymal hamartomas may present before two years of life, with a median age of 10 months (0 - 19 years). The male to female ratio is 2:1, with the right lobe being affected more frequently than the left (6:1).^6,8 However in the present case report, the patient was a seven year old female child and mainly the left lobe liver was affected.

Hepatic cystic mesenchymal hamartomas are mostly asymptomatic and may present as rapid abdominal distention with palpable mass. The rapid distention may represent degeneration of the mesenchyme and fluid accumulation. Other uncommon presentations may be vomiting, fever, constipation and weight loss.⁸ Our patient also presented with an abdominal mass and complaints of nausea and vomiting. Laboratory investigations usually show normal liver function.⁹ The Ultrasound and CT scans may show large, uni or multicystic, mass occupying part of the liver.³ Surgical resection is the mainstream treatment for Hepatic cystic mesenchymal hamartomas. Marsupialization is also an alternative option, especially in cases not amenable to resection.¹⁰ Rarely, aspiration of the fluid is done to relieve discomfort and reduce tension. In the present case, complete excision of the cystic mass along with liver segments 2, 3, 4a of left lobe was undertaken.

Hepatic cystic mesenchymal hamartomas (MH), though rare, should be considered in the differential diagnosis for an upper abdominal lump and surgical excision is considered the best treatment option.

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