Pathological Fracture of the Tibia Due to Lytic Bone Lesion Caused by Hydatidosis with Absence of Systemic Involvement: A Case Report and Review of Literature.

BACKGROUND

This report raises attention to hydatidosis in bone as a neglected lytic osseous disease.

CASE PRESENTATION

The authors reported a case of a 49-year-old female who presented with pain and swelling in the right upper leg. X-ray suggested a lytic lesion in the right proximal tibia. Adenocarcinoma metastasis was suspected, yet, the investigations revealed negative Positron emission tomography (PET) scan metastatic work-up and negative alpha-fetoprotein, Cancer Antigen (CA) 15.3, CA 19.9, CA125, and Carcinoembryonic antigen (CEA). The histopathological evaluation of the extracted core biopsy showed a granulomatous reaction with reactive fibrosis. Immune reactive CD68 cells were recorded in the epithelioid macrophages and foreign body giant cells. Four months later, the patient was presented with a pathological fracture in the upper right leg. Surprisingly, the histopathological evaluation of the Hematoxylin and Eosin sections and the cytological assessment reported pathognomonic structures for hydatid in the form of foreign body giant cells engulfing laminated hyaline eosinophilic material and a scarce number of hooks. The absence of cellular atypia excluded malignancy. Periodic acid schiff highlighted the pathognomonic laminated fragments and granulation tissue. Masson trichrome staining emphasized collagen deposition.

CONCLUSION

Osseous hydatidosis is a neglected disease that may mimic lytic bone tumors. Vague radiological features and scarce parasite-derived structure in histopathology may misinterpret the disease. Raising attention to bone hydatidosis among clinicians is recommended.