|Year : 2007 | Volume
| Issue : 1 | Page : 28-29
Pulmonary adenoid cystic carcinoma : An unusual presentation
Ramakant Dixit1, Paras Nuval2
1 Department of Tuberculosis and Respiratory Medicine, J.L.N. Medical College, Ajmer., India
2 Department of Pathology, J.L.N. Medical College, Ajmer., India
381/26, Ramganj, Ajmer - 305001.
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Adenoid cystic carcinoma is a rare but distinctive salivary gland type malignant neoplasm that arises infrequently in the respiratory tract, where it is largely seen in the trachea or large airways. A 29-year-old female who presented with a peripheral lung mass due to pulmonary adenoid cystic carcinoma is reported in view of its unusual location, early age of presentation and lack of such reports in the recent literature. Lung India 2007; 24 : 28-29
Keywords: Adenoid cystic carcinoma, Peripheral lung tumors.
|How to cite this article:|
Dixit R, Nuval P. Pulmonary adenoid cystic carcinoma : An unusual presentation. Lung India 2007;24:28-9
| Introduction|| |
Adenoid cystic carcinoma is a distinctive type of malignant epithelial neoplasm most commonly encountered in the salivary glands (i.e. submandibular and palate). Other uncommon sites includes seromucinous glands of upper respiratory tract, lacrimal glands, ear canal, tracheobronchial tree, breast, cervix, skin, esophagus and prostate  . In the respiratory tract, tumor typically arises in the trachea and large airways. It is very rarely encountered as primary tumor in the lung parenchyma  .
Adenoid cystic carcinomas occurs most frequently in the fourth to sixth decades of life. It is very rarely seen below 30 years. There is no sex predominance and the etiology is largely unknown , .
The present communication describe a case of adenoid cystic carcinoma lung due to its unusual presentation in form of involvement of lower lobe parenchyma in a patient below the age of 30 years. To the best of authors knowledge, such presentation has not been described in the Indian literature previously.
| Case Report|| |
A 29-year-old woman presented to our hospital with complaints of progressive shortness of breath and occasional haemoptysis of two months duration. There was no history of cough, chest pain or fever. Her past medical history was unremarkable.
General examination was essentially normal with no pallor, clubbing or lymphadenopathy etc. Respiratory system examination revealed dull percussion note and decreased intensity of breath sounds in the right lower lung fields. Other systemic examination did not reveal any abnormality. The chest radiograph revealed a mass in the right lower zone. The hematological and biochemical profile was essentially normal. Fiberoptic bronchoscopy and computerised tomographic examination of thorax could not be performed.
For tissue diagnosis of the lung mass, tru cut needle biopsy of the pulmonary parenchymal lesion was done by per cutaneous transthoracic approach and multiple tiny grayish brown soft tissue pieces were obtained. Histopathological examination of the biopsy specimen revealed nests and columns of uniform malignant cells arranged concentrically around variably sized gland like spaces (pseudocysts). The tumor cells were composed of dense basophilic nuclei without nucleoli and with minimal basophilic cytoplasm. The cyst like spaces were filled with mucoid or hyaline material which were contiguous with the connective tissue stroma of the tumour [Figure 1]. The histological picture was classical of adenoid cystic carcinoma lung with cribriform pattern.
Patient was referred to thoracic surgery department for further management and lost to follow-up thereafter.
| Discussion|| |
Pulmonary adenoid cystic carcinoma is a rare tumour which constitute less than one percent of all primary lung tumours  . Although it forms an extremely small proportion of primary neoplasms arising in the bronchi, its relative incidence in the trachea is much higher where, with squamous cell carcinoma, it comprises the vast majority of primary tumours  . Many authors have emphasized that adenoid cystic carcinoma typically arises in the large airways , , there are some reports that it may arise as peripheral lung tumour , . Gallagher et al  reported a case of pulmonary adenoid cystic carcinoma presenting as peripheral lung mass and multiple pulmonary nodules 11 years after resection of the original tumour. In the same report, authors critically reviewed the literature of peripheral adenoid cystic carcinoma lung and emphasized that approximately 10-15% of patients with pulmonary adenoid cystic carcinoma may present with peripheral tumours. These peripheral tumours presumably arise from glands in small bronchi. In our case also tumour was peripherally located in the lower lobe of lung and histologically confirmed by percutaneous transthoracic needle biopsy.
Most of these tumours are discovered in the middle age; the mean age in two series of 16 and 38 patients was 51 and 45 years, respectively , . It is very rarely seen below the age of 30 years  . In our case, the patients age was 29 year, which is an uncommon age for this tumour to present with.
Pathologically adenoid cystic carcinoma are slowly growing lesions that thickens and narrow the bronchial wall. These are poorly defined, sessile, nodular growth that may ulcerate centrally but more usually infiltrate extensively beneath an intact mucosa, ultimately involving adjacent lung tissue and hilar lymph nodes by direct invasion  . Distant metastasis are more frequent than spread to the regional lymph nodes i.e. lung, bone, brain, liver, soft tissues etc. Histologically three patterns are seen - Cribriform, tubular and solid type. The most frequent and predominant pattern is cribriform, or cylindromatous which is characterized by nests of tumour cells containing numerous, sharply outlined luminal spaces and sometimes containing mucinous secretion within their lumen , . In our case also, the classical cribriform pattern was evident on histopathological examination. The treatment of choice in such tumours is wide to radical surgical excision and postoperative radiotherapy. Radiotherapy improves local tumour control when there is microscopic residual tumour. Despite slow growth and often deceptive benign clinical features, the long term survival is poor and disease stage at the time of diagnosis play an important role in predicting the clinical outcome of patients with these tumours , .
Adenoid cystic carcinoma is a rare tumour characterised by slow but relentless growth. The cause is unknown and no specific genetic or environmental risk factors have been identified. For further research and awareness of this rare cancer, an Adenoid Cystic Carcinoma Organisation International (ACCOI) has been formed which is an allvolunteer non profit organisation maintaining a website with information about adenoid cystic carcinoma at : http:/www.orgsites.com/ca/acco . The organisation provides an online doctors forum for doctors interested in this tumour with an email email@example.com to share information about treatment and research. The website also provides education in form of newsletter and informational sheets  .
We conclude with remark that adenoid cystic carcinoma may present with a peripheral pulmonary mass without tracheal or large airway involvement and in younger age group.
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