In human medical literature, the same term ‘accessory lung or accessory lobe' was renamed as pulmonary sequestration to define abnormal mass of nonfunctioning development of lung tissue anywhere in the body ⁸. Bronchogenic cysts are another congenital anomalies resulting from anomalous development of the ventral foregut; they are usually single but may be multiple. They have been found all along the tracheoesophageal course, pulmonary parenchyma, neck, abdomen, and lumbar regions ⁴. To the best of authors' knowledge, as a lung bud malformation, no concurrent occurrence of pulmonary sequestration and bronchogenic cyst is available in veterinary literature, whereas in human medicine, concurrent occurrence of bronchogenic cyst and pulmonary sequestration was reported in only 3 among the approximately 900 cases of pulmonary sequestrations ⁹. This case report describes morphologically a subcutaneous lung sequestration enmeshed with bronchogenic cyst in a calf.

The mass which had initially been noted on the day of parturition was not associated with dysphagie, airway obstruction or previous trauma. It was ovoid appearance with 5-6 cm in diameter and freely movable and was covered and well protected by the skin. Cytological examination of the needle aspiration revealed the presence of scattered macrophages and a few neutrophil leucocytes. Ventro-dorsal and latero-lateral chest radiographs showed that the mass located in sternal manibrium. After injection of contrast medium, the mass did not showed enchantment. On request of surgical removal of the mass by the owner, the operation site on the lower neck was prepared and after premedication and local infiltration anesthesia, a 15 cm straight incision was made centered over the mass, attached to apertura thoracis cranialis by a fibrovascular pedicle containing an artery and a ligamenteous structure.

The artery was approximately 5-6 mm in diameter. There was apperently no communication with gastrointestinal tract. Following the proper ligation, the mass was completely removed. It weighed 350 g, had fleshy and edematous appereance and measured 5x6x6 cm. Serial sectioning of the specimen revealed a multiocalar cyst, approximately 1 cm in diameter, it's inner surface was separeted and white, containing serous and clear fluid (Fig-1). Formalin fixed tissue samples were processed routinely and paraffin embedded tissue samples were stained with hematoxyline-eosin.

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Figure 1: Section across pulmonary sequestration with a bronchogenic cyst (arrow).

Histological examination of the tissue specimens revealed that the mass was underdeveloped lung tissue which was rich in loose connective tissue along with brochioles and alveolar structures. The lung tissue was covered by both pleura and the skin. Microscopically, the bronchioles were present in excessive number and dilated apparence containing simple columnar or cuboidal epithelium. The brochi were hypoplastic and had no cartilagonous ring. The alveoli were also not fully developed and some alveoli and respiratory bronchioles were dilated. Alveolar spaces contained focally hemosiderin laden macrophages. Focal irregular lymphoid aggregates in paranchymal tissue were also present. Mild to moderate peribronchialar fibrosis and isolated cartiloganeous tissue were the additional findings detected (Figure-2 ). The cyst wall was composed of ciliated pseudostatified columnar epithelium, hyaline cartilagae and mucous glands (Fig-3).

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Figure 2: Figure 2. Small island of hyaline cartilage (c) within the interstitial tissue of the lung tissue, H&E, Bar:20m.m

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Figure 3: The bronchogenic cyst containing respiratory epithelium, muscular layer (m) and cartilagae (c) and mucous glands (arrows), H&E, Bar:50 m.

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