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Year : 2014  |  Volume : 28  |  Issue : 3  |  Page : 190-192

Congenital cystic malformation masquerading as a lung abscess in an adult: A report of a rare case

Department of Pathology, Indira Gandhi Government Medical College, Nagpur, Maharashtra, India

Date of Web Publication5-Jan-2015

Correspondence Address:
Sandhya V Poflee
Department of Pathology, Indira Gandhi Government Medical college, Nagpur, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0972-4958.148523

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A 19 year-old male was getting admitted repeatedly, for complaints of cough with expectoration and fever since last 10 years. On the basis of clinical examination and radiological investigations lung abscess of right lower lobe was suspected. Non-functioning right lung lobe of the patient was removed surgically and sent for histopathological examination. Histopathology showed it to be cystic adenomatoid malformation of lung type I, with no evidence of any other specific disease. Congenital cystic adenomatoid malformation (CCAM) is an anomaly of lung development characterized by proliferation of abnormal bronchiolar structures of varying sizes and distribution. It is usually diagnosed in infancy. It is rare in adults. Awareness about this entity help clinicians while making differential diagnosis of recurrent pulmonary infection limited to one lobe. Morphological identification of CCAM is important as Type I CCAM; the most frequent subtype is associated with an increased incidence of malignant transformation.

Keywords: Adult, Congenital cystic adenomatoid malformation, Lung

How to cite this article:
Poflee SV, Zutshi A, Bhadarge PS, Shrivastava AC. Congenital cystic malformation masquerading as a lung abscess in an adult: A report of a rare case. J Med Soc 2014;28:190-2

How to cite this URL:
Poflee SV, Zutshi A, Bhadarge PS, Shrivastava AC. Congenital cystic malformation masquerading as a lung abscess in an adult: A report of a rare case. J Med Soc [serial online] 2014 [cited 2022 Dec 1];28:190-2. Available from:

  Introduction Top

Congenital cystic adenomatoid malformations (CCAM) also known as congenital pulmonary airway disease is a developmental, non-hereditary hamartomatous abnormality of lung of unknown cause. [1] Occurrence in adults is rare and the disease may remain asymptomatic, may be a chance finding or may be revealed by lung inflammatory process. [2]

CCAM has been classified into five morphological types. If CCAM is suspected as the cause of repeated pulmonary infection limited to single lobe, patient should be treated early with surgical removal of the affected lobe as Type I CCAM the most frequent subtype, is associated with risk of malignant transformation. [3]

  Case Report Top

A 19 year-old male was admitted with complaints of cough with expectoration and moderate grade fever since one month, along with an episode of haemoptysis eight days prior to admission. There was no history of dyspnoea, chest pain or weight loss. He gave peculiar history of productive cough and fever on and off since last 10 years for which he was treated at various private hospitals as a case of recurrent pulmonary infection with only temporary relief from his symptoms. He was put on anti-tuberculous treatment for 6 months without much improvement. There was nothing significant in family and personal history.

On examination he was a thin built young man with markedly diminished air entry in lower zone of right lung. Rest of the general and systemic examination was normal.

His chest radiograph revealed an air-fluid level in right lung lower zone [Figure 1]a. Possibility of hydropneumothorax or lung abscess was offered. USG thorax showed similar findings.
Figure 1 : (a) X-ray chest PA view: A single cavity seen in right lower lobe with air-fluid level, (b) CT thorax: Single large cyst seen in right. Lower lung lobe showing incomplete septae and air-fluid level

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Subsequent Computed Tomography (CT) thorax demonstrated a large cystic lesion with air-fluid level and incomplete septations in lower lobe of right lung with possibility of post infective cystic lesion [Figure 1]b.{Figure 1}

Other investigations revealed neutrophilic leucocytosis, non-reactive ELISA for HIV I and II, negative Zeihl Neelsen staining for tubercle bacilli on sputum as well as pleural fluid. There was no mycobacterial growth on culture of sputum and pleural fluid.

Based on the clinical and investigative data diagnosis of lung abscess was made and patient was subjected to surgical resection of the affected lung lobe.

Gross examination of the specimen showed single lung lobe of 12 Χ 8 Χ 6 cm with a large cystic cavity measuring 8 Χ 7 Χ 6 cm with incomplete septae without contents. Microscopic examination of the sections from the cyst showed multiple irregular cleft-like spaces of varying sizes lined by pseudostratified columnar ciliated epithelium [Figure 2] showing papillary infolding at places. Below the lining epithelium loose fibro-vascular tissue and prominent muscle layer were seen. None of the spaces showed presence of cartilage in the wall [Figure 2]. Surrounding lung parenchyma was congested and edematous with no pleural changes. There was no evidence of necrosis, granuloma formation or any other specific pathology in the cavity wall or surrounding lung tissue.
Figure 2 : Multiple irregular cyst-like spaces in lung parenchyma (Haemtoxylin and Eosin 100×). Inset: Pseudostratified ciliated columnar epithelial cyst lining (400×)

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A diagnosis of congenital cystic adenomatoid malformation (CCAM) of lung type I was made. The patient had uneventful post-operative course and he was completely asymptomatic at subsequent follow-up visits.

  Discussion Top

CCAM represents a continuum of hamartomatous cystic lung lesions with an incidence of 1 in 25000-35000 pregnancies. [4] It is thought to result due to arrested development of lung during pseudoglandular and saccular period (7-35 weeks of intrauterine life). [5] The term CCAM was first introduced in 1949. It is characterized by cysts of varying sizes and/or adenomatoid proliferation resembling bronchioles. There is no sex predilection. Both lungs are equally involved and single lobe disease is more common than multi-lobe disease with predilection for lower lobe involvement.

CCAM is most commonly found in neonates and up-to 90% of cases are identified within first 2 years of life. [6] In utero-diagnosis by ultrasound is known. On chest radiograph the findings are variable and non-specific. CT scan is the investigation of choice. In adults CCAM is rare and may present as involvement of entire lung lobe by irregular cystic mass or as single well-defined cyst of upto 10-cm diameter. [7] CCAM has been classified into five types by Stocker et al in 1977 depending on the size and number of cysts and the lining epithelium.

A single large cyst seen in an adult has to be differentiated from more commonly occurring pulmonary lesions like intralobar sequestration, intrapulmonary cyst, lung abscess and bronchiectasis. Intralobar sequestration is diagnosed during operative procedure by presence of anomalous blood supply to the affected lobe. Microscopic examination of the surgical specimen is needed to differentiate other lesions like intrapulmonary cyst that lacks prominent muscle and shows presence of cartilage in the wall. In lung abscess there is destruction of lung parenchyma and presence of inflammatory response and fibrosis in the wall of abscess. Post-infectious bronchiectasis usually occurs bilaterally and shows honeycombing of lung with pleural changes which are lacking in CCAM. On microscopy presence of cartilage in the wall, marked suppurative inflammation and squamous metaplasia of the lining are seen in bronchiectasis. [8]

Complications such as recurrent pneumonia, spontaneous pneumothorax, abscess formation, haemoptysis and malignancies such as bronchioloalveolar carcinoma, rhabdomyosarcoma, pulmonary blastoma and squamous cell carcinoma can arise in an unexcised CCAM lesion. [9] Of this neoplastic transformation has worst prognosis and is usually seen in older children or young adults.

Surgical excision remains the mainstay of treatment at diagnosis in all cases. [10]

In conclusion if a patient presents with repeated respiratory infection limited to one lobe of lung with non-resolving cavitary lesion on radiology, a diagnosis of CCAM should be suspected. It is important to examine the resected lung specimen thoroughly in order to recognize this entity and to know the type of CCAM that has direct relation to the prognosis of the patient. Early diagnosis of occurrence of malignant change is possible by morphological examination of the excised lung lobe.

  Acknowledgement Top

General support by departmental chair: Professor and Head, Department of Pathology, Professor and Head, Department of Radiology.

  References Top

Chikkannaiah P, Kangle R, Hawal M. Congenital cystic adenomatoid malformation of lung: Report of two cases with review of literature. Lung India 2013;30:215-8.  Back to cited text no. 1
[PUBMED]  Medknow Journal  
Morelli L, Piscioli I, Licci S, Donato S, Catalucci A, Del Nonno F. Pulmonary congenital cystic adenomatoid malformation, type I, presenting as a single cyst of the middle lobe in an adult: Case report. Diagn Pathol 2007;2:17.  Back to cited text no. 2
Harini N, Chakravarthy R, Archana L. Congenital pulmonary airway malformation with mucoepidermoid carcinoma: A case report and review of literature. Indian J Pathol Microbiol 2012;55:540-2.  Back to cited text no. 3
[PUBMED]  Medknow Journal  
Sahu S, Muthuvel S, Naware SS, Dhavala SS. Congenital Cystic Adenomatoid Malformation of Lung. Med J Armed Forces India 2008;64:268-9.  Back to cited text no. 4
Sood M, Sharma S. Congenital cystic adenomatoid malformation of lung-A case report. Curr Pediatr Res 2011;15:61-3.  Back to cited text no. 5
Annam V, Korishetty S I, Yelikar BR, Hippargi SB, Shivalingappa DB. Bilateral congenital cystic adenomatoid malformation, stocker type III with associated findings and review of literature. Indian J Pathol Microbiol 2010;53:331-3.  Back to cited text no. 6
[PUBMED]  Medknow Journal  
Khan NU, Jones MT, Greaves M. Case report: Congenital cystic adenomatoid malformation of an entire lung in a 33-year-old man: A case report and review of the literature. Br J Radiol 2008;81:e276-8.  Back to cited text no. 7
Rosai J. Respiratory tract. In: Rosai J, editor. Rosai and Ackerman's Surgical Pathology volume 1. 10 th ed. New York: Mosby;2012.p.348-52.  Back to cited text no. 8
Dahabreh J, Zisis C, Vassiliou M, Arnogiannaki N. Congenital cystic adenomatoid malformation in an adult presenting as lung abscess. Eur J Cardiothorac Surg 2000;18:720-3.  Back to cited text no. 9
Luján M, Bosque M, Mirapeix RM, Marco MT, Asensio O, Domingo C. Late-onset congenital cystic adenomatoid malformation of the lung. Embryology, clinical symptomatology, diagnostic procedures, therapeutic approach and clinical follow-up. Respiration 2002;69:148-54.  Back to cited text no. 10


  [Figure 1], [Figure 2]

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