Asian Cardiovasc Thorac Ann 2001;9:62-64
© 2001 Asia Publishing EXchange Pte Ltd
Intrapulmonary Heterotopic Pancreas Presenting As Lung Abscess
Ghulam Nabi Lone, MCh,
Ghulam Nabi Sofi, MD,1,
Mohammed Akbar Bhat, MCh,
Abdul Majid Dar, MCh,
Abdul Gani Ahanger, MCh,
Noor Ali, MCh
Department of Cardiovascular and Thoracic Surgery
1 Department of Pathology Sheri Kashmir Institute of Medical Sciences Kashmir, India
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For reprint information contact: Ghulam Nabi Lone, MCh Tel: 91 194 42 2592 Fax: 91 194 42 3470 email: root{at}skims.ren.nic.in Department of Cardiovascular and Thoracic Surgery, Sheri Kashmir Institute of Medical Sciences, P.O. Box 1222, GPO Srinagar, Kashmir 190001, India.
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Abstract
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Ectopic pancreas in the lung is an extremely rare entity. A 17-year-old girl presented with a cystic lesion in the lower lobe of the right lung with features of sepsis. Exploration revealed a huge infected cyst bearing a nodule on its wall, in the right lower lobe, extending to the middle lobe, which proved to be pancreatic in origin (exocrine tissue only) on histopathology.
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Introduction
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The presence of pancreatic tissue outside its usual location and without anatomic relation of either continuity or vascularization with the pancreas proper (pancreatic ectopia) is no longer considered a rare entity. Accessory pancreas have been found at various sites but intra-pulmonary pancreatic ectopia is extremely uncommon.1–3
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Case Report
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A 17-year-old unmarried girl presented with recurrent episodes of fever, chest pain, productive cough, breath-lessness, and occasional hemoptysis. She had received antitubercular drugs (isoniazid, ethambutol, rifampicin, and pyrazinamide) previously in another hospital. How-ever, she had no relief from her symptoms. On examina-tion, she was found to be febrile (temperature, 37.7°C) and anemic. She had a pulse rate of 104 beatsámin–1, blood pressure of 120/70 mm Hg, and a respiratory rate of 24 breathsámin–1. Chest examination revealed diminished breath sounds and coarse crepitations at the right base, with a patch of bronchial breathing in the infrascapular area. Her hemoglobin was 95 gáL–1 and the total leukocyte count was 8.2 x 109/L with predominant polymorphonuclear leukocytosis. Liver and renal function tests were normal. A random blood sugar level was 1.04 gáL–1. There was no evidence of pulmonary tuber-culosis. Casoni's test and an enzyme-linked immunosorbent assay for hydatidosis were negative (hydatidosis is very common in Kashmir). Chest radiography (Figures 1A and 1B
) demonstrated a huge radiopaque shadow with an air-fluid level suggestive of a lung abscess in the right lower and mid zones. Bronchoscopy ruled out an endo-bronchial lesion. However, the right lower lobe bronchus was partially obstructed due to extrinsic compression, and it contained some purulent material. Fluid from bronchoalveolar lavage did not reveal any malignant cells. Intensive medical therapy for 6 weeks failed to relieve the symptoms or resolve the lung abscess radiologically. Computed tomography of the thorax (poor quality film) demonstrated an area of breakdown adjacent to the cystic lesion, with an eccentric intracystic mass lesion in the right lower lobe. An infected cavitary neoplasm was suspected. On exploration via a right posterolateral thoracotomy, the whole of the right lung was found to be adherent to the parietal pleura. A huge cystic lesion, 10 x 8 cm in size, communicating with the lower lobar bronchus, was displayed in the right lower lobe and contained a dirty white fluid admixed with calcified concretions. The cystic cavity had a grayish white nodular lesion, 3 x 2.5 cm in size, arising from the cyst, inseparable from the parenchyma, and partially filling the cavity. The cyst was compressing the surrounding lung tissue. An abscess, 4 x 3 cm in size, as well as several microabscesses were seen in the surrounding parenchyma of the lower lobe in the medial and superior aspect of the cyst. One of the microabscesses had ruptured into the pleural cavity. No anomalous blood supply from the aorta was detected. A frozen section study was inconclusive. Hence, in view of the strong suspicion of neoplasia, a right lower lobectomy was performed and the chest cavity was drained by 2 chest tubes. Culture of the purulent material from the abscess cavity grew Streptococcus pyogenes. The post-operative period was uneventful.
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Figure 1. Chest radiography. (A) Posteroanterior view demonstrating a huge shadow with an air-fluid level in the right lower and mid zones. (B) Lateral thoracic view revealing the same shadow with an air-fluid level at the top, overlapping the cardiac silhouette.
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The excised lesion constituted a thin-walled cyst, 10 x 8 cm in diameter, with a smooth inner surface and an eccentric nodule (3 x 2.5 cm) embedded in spongy reddish tissue suggesting lung parenchyma. The nodule was lobulated, grayish white in color, and the cyst was full of purulent material and calcified concretions. The cyst wall consisted of a thin layer of fibrous tissue with occasional immature smooth muscle cells, and it was lined by pseudostratified epithelium. Surrounding lung tissue showed focal collapse and deposition of carbon particles. In all sections of the specimen, normal bronchioles with ciliated cuboidal epithelium and surrounding collagen, elastic, and smooth muscle fibers were seen. Oriented about the bronchioles were acini and lobules of well-differentiated pancreatic tissue (exocrine component only) that was separated from the contiguous pulmonary tissue by loose areolar tissue forming interlobular septa. Other possible ectopic tissues were not observed. In addition, there was scattered infiltration with polymorphonuclear cells and lymphocytes in the periphery. No cartilaginous elements were seen in the cyst wall. These features were consistent with heterotopic pancreas embedded in the lung parenchyma (Figure 2).
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Figure 2. Photomicrograph of the resected specimen revealing acini and lobules of heterotopic pancreatic tissue (H) oriented about the bronchiolar elements (B). Hematoxylin and eosin stain, original magnification x40.
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Discussion
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Usually, pyogenic lung abscess follows aspiration, dental infections, endobronchial obstruction secondary to foreign body impaction, or tumors. However, we have observed hydatid cystic disease with abscess formation to be a common surgical entity in the Kashmir valley. In the lung, cystic lesions that are likely to become infected include congenital lesions (bronchogenic cyst, cystic adenomatoid malformations, epithelial cysts, sequestration of lung, and rarely, enterogenic cysts) as well as acquired lesions such as hydatid cysts. When differentiating, emphysematous cysts and diaphragmatic hernia should not be ignored. In addition, chronic lung abscess due to tuberculosis or a fungal infection needs to be differentiated so that proper treatment is instituted early. However, ectopic pancreatic tissue with a cyst and subsequent abscess formation as observed in our case, has not been reported previously to our knowledge.
Heterotopic pancreas are common at diverse areas in the gastrointestinal tract and the frequency of ectopic pancreas has been reported from autopsy material to range from 0.62% to 5.6%.1 Common sites are the stomach, small intestine, Meckel's diverticulum, common bile duct, gall bladder, hilum of the spleen, esophagus, and umbilicus.2 Yamagiwa and colleagues3 described an infant with a rare type of esophagotracheal anomaly associated with heterotopic pancreas of the esophagus. The upper pouch containing the pancreatic tissue reached below the carina and the distal esophagus was connected to the trachea 2 cm above the carina. Kellett and colleagues4 reported 2 singular intrapulmonary lesions of developmental origin: one was a cyst characterized by the presence of adjoining heteroplastic gastrointestinal epithelium; the other was a sequestrated intralobar lung consisting of well-differentiated pancreatic tissue with ducts communicating with the bronchi, it was accompanied by an intrapulmonary cyst lined by bronchial mucosa and an attached nodule composed of well-differentiated pancreatic tissue. Our observations were consistent with these findings. Shillitoe and Wilson5 reported one case of heteroplastic pancreas in the thorax; there was a huge mediastinal cyst with abundant pancreatic tissue in its wall, containing mucus-secreting columnar epithelium.
The existence of pancreatic tissue in the lung reminds us of the endodermal origin of the bronchial tree and can be explained on the basis of heteroplasia of the bronchial endoderm. The communication of the cyst with the bronchus and orientation of bronchiolar elements about the pancreatic acini, point towards the bronchial origin of this tissue. Heterotopic pancreas usually remains asymp-tomatic. However, cystic degeneration and obstructive complications have been seen when the cyst arises from the submucosa of the stomach and esophagus, and small intestine, respectively.2 Pancreatitis, hemorrhage, and necrosis are also known to occur. However, possible sequelae of intrapulmonary ectopic pancreas have not been reported. Both benign and malignant changes in heterotopic pancreatic tissue located in the gastrointestinal tract have been observed and a similar possibility cannot be ruled out with intrapulmonary pancreas.1 The hetero-topic tissue is not always completely formed and differentiated. Hence, changes of neoplastic transformation are more likely in an incompletely developed tissue at an aberrant location where it is subjected to irritation, warranting surgical extirpation.
A mass of heterotopic pancreatic tissue can be mistaken both radiologically and at operation for a malignant growth with consequent unnecessary operation. Therefore, it is of utmost importance to keep in mind the possibility of this rare cystic lesion. A complicated lesion should be treated surgically.
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References
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Barbosa JE, Dockerty BM, Waugh MJ. Pancreatic heteroplasia. J Surg Gynecol Obstet 1946;82:527–42.
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Ermak TH, Grendell JH, Brandborg LL. Developmental anomalies of pancreas. In: Sleisenger MH, Fordtran JS, editors. Gastrointestinal disease. Vol. 11. 3rd ed. Philadelphia: Saunders, 1983:1415–8.
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Yamagiwa I, Obata K, Ouchi T, Sotoda Y, Shimazaki Y. Heterotopic pancreas of the esophagus associated with a rare type of esophageal atresia. Ann Thorac Surg 1998; 65:1143–4.[Abstract/Free Full Text]
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Kellett HS, Lipphard D, Willis RA. Two unusual examples of heteroplasia in the lung. J Pathol Bacteriol 1962;84: 421–5.[Medline]
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Shillitoe AJ, Wilson JE. Heteroplastic pancreas in thorax. J Thorac Surg 1957;34:810.
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Abstract
Introduction
