ABSTRACT
Hydatid cyst of lungs is mainly diagnosed by imaging procedures such as chest Roentgenogram and chest CT Scan. In endemic area, hydatid cyst may be discovered during the surgery appearing in a form which is not usually identified with typical Hydatidosis of lungs. The objective of this study was to give a description of the most important atypical radiological presentation of lung Hydatidosis. All the patients diagnosed as having pulmonary Hydatidosis through a surgical exploration were included in this study. Standard chest Roentgenograms and computed Tomographies were evaluated before the surgery for diagnosing any lung cyst or unknown lesion. Radiological findings were divided into two categories: 1-Typical Hydatid cysts which have already been described in literature as having imaging presentations such as intact cyst, water lily sign and crescent sign. 2- Atypical Hydatid cysts that do not resemble any feature of typical Hydatid cysts as mentioned above. 1614 subjects who had already been diagnosed with pulmonary Hydatidosis over a period of 28 years went under surgical operations. Seventy nine of them received standard Thoracic CT scan. Atypical cysts were detected in 35% of the subjects that were X-rayed by chest and in 32 of them [40.5%] who received CT Scan. The most frequent chief complaint was coughing as reported by 68 [87%] of the cases. None of the clinical and demographic findings were significantly more frequent in the subjects with atypical Hydatid cyst. The most frequent manifestation illustrated in the radiological pictures was thick cavity wall in 9 subjects [28%]. Other findings were as follows: solid mass in 7 [21%], abscess in 6 [18%], consolidation in 3 [9%], fungus ball in 3 [9%], collapse [atelectasis] in 2 [6%] and round pneumonia in 2 [6%]. Cavity was significantly more frequently seen in the right lung [90%] and mass like opacity was significantly more frequent in the lower lung field [100%]. Hydatid cyst showing atypical features is relatively common; thus, physicians should be cautious about the possibility of Hydatid cyst while evaluating most of the radiological pictures of the lung, no matter what the localization, size and count of the lesion