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Hydatid Cyst of the Temporal Bone

An Exceptional Location

Habib Bourguiba Hospital 3029 Sfax, Tunisia
King Khaled Military Hospital Hafr Al Batin 31991, Saudi Arabia
Habib Bourguiba Hospital 3029 Sfax, Tunisia

Hydatid disease in bone is rare (1-2% of all cases). Most cases have been observed in adults, with the spine and pelvis being the predominant locations. We describe an exceptional case of hydatid disease in the temporal bone and report the CT and MR findings. To our knowledge, only three cases have been previously reported in the literature and none were documented on MR imaging.

A 24-year-old man was admitted to the hospital for recurrent left-sided temporal swelling, progressively increasing over 1 year, with recurrent left-sided otalgia and vertigo. He had undergone surgery for a similar swelling in the same area twice, 8 and 3 years earlier. He had also undergone surgery for a hydatid cyst of the right hepatic lobe 5 years earlier. On examination, the swelling was painful and firm, measuring 5 x 4 cm. CT scans obtained before and after injection of contrast material (Fig. 6A) showed an ill-defined heterogeneous mass of mixed density that was located in the left petrous bone and displayed endo- and exocranial extensions. A small left-sided temporal arachnoid cyst was also observed (Fig. 6A). Fine cuts of the petrous bone (Fig. 6B) showed left-sided tympanomastoidal geographic osteolysis with discrete peripheral osteosclerosis. The tegmen tympani (Fig. 6B) and the ossicular chain were involved by the destructive process. T1- and T2-weighted MR images obtained before and after gadolinium administration documented a left-sided temporal extradural multilocular cystic mass with endo- and exocranial extensions (Figs. 6C and 6D). The wall of the daughter cyst was thin and regular, and the cuticular membrane showed intense enhancement. The clinical findings and images were suggestive of a hydatid cyst in the temporal bone. This diagnosis was subsequently supported by positive findings at serology for hydatid. At surgery, an extradural multivesicular hydatid cyst was found and numerous daughter cysts of various sizes were removed.

View larger version (159K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 6A. —24-year-old man who presented with recurrent left-sided temporal swelling and recurrent left-sided otalgia and vertigo. On examination, swelling was painful and firm, measuring 5 x 4 cm. Transverse contrast-enhanced CT scan shows multiloculated hypodense mass in left temporal bone and osteolysis of squamous bone.

View larger version (135K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 6B. —24-year-old man who presented with recurrent left-sided temporal swelling and recurrent left-sided otalgia and vertigo. On examination, swelling was painful and firm, measuring 5 x 4 cm. Coronal high-resolution petrous CT scan shows left-sided mastoidotympanic geographic osteolysis.

View larger version (165K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 6C. —24-year-old man who presented with recurrent left-sided temporal swelling and recurrent left-sided otalgia and vertigo. On examination, swelling was painful and firm, measuring 5 x 4 cm. Transverse T2-weighted MR image shows left-sided temporal multiloculated cystic mass with multiple daughter cysts and left-sided temporal arachnoid cyst.

View larger version (167K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 6D. —24-year-old man who presented with recurrent left-sided temporal swelling and recurrent left-sided otalgia and vertigo. On examination, swelling was painful and firm, measuring 5 x 4 cm. Transverse contrast-enhanced T1-weighted MR image shows intense contrast enhancement of cuticular membrane.

This case highlights the imaging pattern of skull hydatid disease. Bone is usually considered the primary location in most cases without visceral involvement (75-88%) [1, 2]. Histologically, development of echinococcus starts in the bone marrow, progresses by diffuse vesicular proliferation, and spreads by contiguity over the skeleton and the surrounding structures including soft tissues. Joint locations are rare despite epiphyseal involvement. Bone echinococcosis most often affects the spine and pelvis, whereas it rarely involves long bones. Skull locations are uncommon [2, 3]. In a review of the literature, we found only three reports that described temporal bone involvement [4]. Therefore, imaging features of this lesion are still poorly documented. Conventional radiography shows a variable-sized ill-delineated osteolysis without osteosclerosis [2, 3]. CT scans obtained before and after infusion of contrast material show the multivesicular pattern of the lesion and reveal its endo- and exocranial extensions [2, 3].

Our case is the first to be documented on MR imaging. We performed spin-echo T1- and T2-weighed MR sequences before and after administration of paramagnetic contrast material. These images allowed identification of the relationship of the cyst with dura and the temporal lobe and of its endo- and extracranial extensions. Multiplanar fine cuts clearly illustrated the multivesicular pattern of the cyst, which displayed regular enhancement in the cuticular membrane. The imaging features of the lesion are strongly suggestive of the diagnosis.

The removal of daughter cysts and the cuticular membrane at surgery allowed confirmation of diagnosis. Excision is often incomplete, thus explaining frequent recurrences.

References

1. Gharbi HA, Hassine W, Brauner M, Dupuch K. Ultrasound examination of the liver. Radiology 1981;139:459 -463[Abstract/Free Full Text]
2. Jlidi R, Yaakoubi MT, Ladab MF, Ben Ayache M, Ghannouchi G, Moula T. The hydatid disease of bone (12 cases). Ann Pathol 1992;12:98 -101[Medline]
3. Bouhaouala MH, Ladab MF, Ben Hammouda M, Atalla R, Hamza H, Gannouni A. Radiologie de l'hydatidose: feuill. Radiologe 1989;29:133 -134
4. Behari S, Banerji D, Phadke RV, Shukla S, Krishnani N, Chhabra DK. Multiple infected extradural parasellar hydatid cysts. Surg Neurol 1997;48:53 -57[Medline]

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This Article Figures Only Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Ennouri, S. Articles by Mnif, J. Search for Related Content PubMed PubMed Citation Articles by Ennouri, S. Articles by Mnif, J. Social Bookmarking                      What's this?