Fine Needle Aspiration Cytology of Mesenchymal Hamartoma of the Liver

Abstract

Mesenchymal hamartoma (MH) of the liver constitutes the third or fourth most common tumor of the liver in childhood and occurs most commonly in the first two years of life. MHs of the liver are seldom aspirated, and reports on the role of fine needle aspiration (FNA) in the diagnosis of MH are scarce. Clinically, cytologically and even histologically, MH can be mistaken for a number of reactive and neoplastic hepatic lesions that may occur in children under 2 years of age. A 10-month-old Pakistani female presented with a history of a right-sided, nonpainful abdominal swelling. Abdominal computed tomography showed a large, partly solid and partly cystic, heterogeneous hepatic mass. FNA cytology showed clusters of both epithelial and mesenchymal/spindle-shaped cells with pieces of loose connective tissue. A cytologic differential diagnosis of mesenchymal hepatic hamartoma and hepatoblastoma of the possible mixed mesenchymal/epithelial subtype was rendered. The histopathologic diagnosis of the resected tumor mass was benign mesenchymal hamartoma of the liver. In children under 2 years of age who present with partly solid and partly cystic hepatic masses, the possibility of MH of the liver should be considered. FNA has a role in the diagnosis of MH. The cytopathologist should be aware of the patient's age, radiologic features and cytologic appearances of this rare, benign neoplasm. Histologic examination of tru-cut biopsies and immunohistochemical stains can help to exclude other pediatric neoplasms that may show cytologic features similar to or mimicking those of MH.