Cytologic diagnosis of fibrous hamartoma of infancy: a case report of a rare soft tissue lesion.

BACKGROUND: Fibrous hamartoma of infancy (FHI) is a rare, benign lesion seen in the first 2 years of life. Despite adequate histopathologic descriptions, reports of it in the cytology literature are rare.

CASE: A 6-month-old male infant presented with an asymptomatic nodule in left anterior axillary fold. The nodule was noticed 6 weeks before presentation. On local examination, it was mobile and rubbery. Considering the endemicity, a presumptive clinical diagnosis of tuberculous lymphadenitis was made. Fine needle aspiration yielded moderately cellular smears composed of short spindle cells in a greasy background admixed with a few adipocytes. No mitosis or abnormal chromatin pattern was seen. In view of the young age of the patient, a cytologic impression of benign lesion or hamartoma was made. Excision of the nodule and histopathologic examination revealed it as FHI.

CONCLUSION: The cytologist should be aware of the cytologic features of FHI, so that in the proper clinical setting this diagnosis can be made with certainty. The mixture of adipose tissue and bland spindle cells is helpful to differentiate this lesion from other infantile soft tissue lesions.