|Year : 2020 | Volume
| Issue : 2 | Page : 102-105
Solitary pulmonary nodule − Pulmonary hamartoma
Pooja Khari, Shalini Mullick, Devesh Chauhan
Department of Pathology, National Institute of Tuberculosis and Respiratory Diseases, New Delhi, India
|Date of Submission||26-Mar-2020|
|Date of Decision||01-Jun-2020|
|Date of Acceptance||20-Jun-2020|
|Date of Web Publication||10-Sep-2020|
Dr. Pooja Khari
MD Pathology, 1898-A, Uday Chand Marg, Kotla Mubarakpur, Delhi 110003
Source of Support: None, Conflict of Interest: None
Pulmonary hamartomas are rare, benign tumours of lung and are composed of an abnormal mixture of epithelial and mesenchymal elements. They usually present as single, round nodules with distinct boundaries and are mostly asymptomatic. We present a case of 45 years old female who presented with cough, chest pain and dyspnea with few episodes of hemoptysis. Computed tomography (CT) scan of thorax showed a well-defined non enhancing mass lesion measuring 4 × 3.2 cm seen in the left lower lobe. Wedge resection was done. Histopathological examination confirmed the diagnosis of pulmonary hamartoma.
Keywords: Benign tumours, pulmonary hamartoma
|How to cite this article:|
Khari P, Mullick S, Chauhan D. Solitary pulmonary nodule − Pulmonary hamartoma. J Assoc Chest Physicians 2020;8:102-5
Pulmonary chondroid hamartoma can present as pulmonary nodule, can be solitary or multiple. They mimic lung carcinoma both radiologically and clinically so it is important to differentiate between the two. The treatment of hamartoma is usually conservative. Also in most cases their growth is slow but they may grow rapidly and show malignant transformation.
| Introduction|| |
Hamartomas are disorganized masses composed of tissue elements which are normally found at that particular site. Pulmonary hamartomas are rare but the most common benign mass lesions of the lung. They are usually found in adult males with a peak incidence in the fifth decade of life. The estimated incidence of pulmonary hamartoma is 0.025–0.32%. Radiologically, they are typically described as coin lesions. Identification of ‘popcorn-like’ calcification on plain radiograph is diagnostic when present. Histologically, they show a mixture of mature mesenchymal tissue like adipose tissue, cartilage, bone, smooth muscle bundles and fibromyxoid tissue in varying proportions. Most patients with pulmonary hamartoma are asymptomatic.
| Case report|| |
We present a case of 45 years old female who presented with cough, chest pain and dyspnea on and off since one month. There was no history of fever or weight loss. She had few episodes of hemoptysis. Routine blood and biochemical parameters were within the normal limits. Computed tomography (CT) scan of thorax showed a well-defined, non enhancing mass lesion measuring 4 × 3.2 cm seen in the left lower lobe of lung [Figure 1].
|Figure 1 CT scan of thorax showing mass lesion in left lower lobe of lung|
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We received left lower lobe wedge measuring 6 × 4 × 3cm, on sectioning a circumscribed grey white nodule measuring 4 × 3.5 cm was seen [Figure 2]. The nodule showed areas of congestion and calcification. Also received were lymph nodes − single node from station five measuring 1 × 0.3cm and three lymph nodes from station nine, largest measuring 1 × 0.5cm and smallest measuring 0.5 × 0.3cm.
|Figure 2 Cut section of wedge from left lower lobe of lung showing circumscribed grey white nodule m/s 4 × 3.5 cm|
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Microscopic examination from nodule showed lung tissue with a circumscribed non infiltrative lesion with a lobular architecture. The lesion comprised mainly of lobules of mature and immature cartilage interspersed with areas of myxoid change [Figure 3]. Mature adipose tissue was seen along with focal deposits of brown fat. Interspersed slit like spaces lined by cuboidal to ciliated columnar epithelium were also noted. All these features were consistent with pulmonary hamartoma. Adjacent lung showed non-specific features of inflammation and congestion. Tissue sent as lymph node station five showed non-specific histology and those from station nine showed reactive changes.
|Figure 3 Microscopic examination shows lobules of mature and immature cartilage with areas of myxoid change and few slit like spaces lined by cuboidal to ciliated coloumnar epithelium. (H and E, 400X)|
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| Discussion|| |
Hamartomas are benign lesions composed of disorganized mixture of epithelial and mesenchymal elements, especially cartilage. When chondroid tissue predominates in the composition of the hamartoma, it is called as chondroid hamartoma. Chondroid hamartomas are rare benign lesions of the lung constituting one percent of pulmonary hamartomas. Pulmonary hamartoma was first described by Albrecht in 1904. They are rare but most common benign tumor-like lesions of the lung and also termed as hamartochondroma, chondromatous hamartoma, adeno-chondroma and mesenchymoma., A classical lesion is non-organized mixture of epithelial and mesenchymal components such as of fibromyxoid stroma, adipose tissue, cartilage, smooth muscle cells and respiratory epithelium. Occasionally bone and bone marrow can be present., Cytogenetic analysis of pulmonary hamartomas showed abnormal karyotype and revealed recombinations between chromosomal bands 6p21 and 14q24, which supported the theory that a hamartoma may be considered as a true neoplasm.
Most Hamartomas are seen in fifth to sixth decade of life with male predominance.
Depending upon their location in the lung, pulmonary chondroid hamartomas are classified as peripheral parenchymal type and central endobronchial type. Peripheral type of chondroid hamartoma accounts for over 90% of all chondroid hamartomas. They take origin from small bronchi and are generally asymptomatic. In contrast, the endobronchial type arises from large bronchi, is less frequent, and is often associated with symptoms of obstruction.
Radiologically, on chest X-ray these appear as smooth well-circumscribed mass with lobulated or bosselated margins, associated with calcifications. Chondroid hamartomas account for seven to fourteen percent of pulmonary coin lesions. Calcifications are often present in a diffuse or popcorn distribution (popcorn calcification). In the CT scan of chest, well-defined sharply marginated lesion showing multiple intralesional hyperdense areas are noted. Alternating areas of fat and calcifications may be seen. The presence of fat density in a peripheral, solitary lesion is strongly suggestive of benign hamartoma. Bronchoscopically, the lesions are smooth, fleshy, pedunculated mass that may be tan to pink. The lesions are often polypoid, either sessile or with a thin pedicle.
Histopathology of chondroid hamartoma shows predominance of islands of mature cartilage admixed with fat, fibromyxoid stroma, and slit-like spaces lined by respiratory type of epithelium. In the endobronchial type of chondroid hamartoma, greater proportion of fat and less epithelial-lined spaces are noted. The differential diagnosis of chondroid hamartomas includes bronchopulmonary chondroma, pleuropulmonary blastoma, and chondrosarcoma. In bronchopulmonary chondroma, the mixture of mesenchymal elements present in chondroid hamartoma is not seen. It consists predominantly of cartilage without cleft-like spaces lined by respiratory epithelium. It lies in continuation with the bronchial cartilage. Pleuropulmonary blastomas are mainly neoplasms of children. The cartilage, fat, and muscle present in pleuropulmonary blastoma are immature whereas in chondroid hamartomas, mature tissue is seen.
Immunohistochemically, some of the spindle cells of hamartoma have features of myoepithelial cells exhibitimg actin and S-100 protein immunopositivity. Furthermore, there may be expression of estrogen receptor, progesterone receptor, and androgen receptor (in male patients), in most of the myoepithelial-like cells.It can be associated with Carney’s triad, which is a rare combination of three unusual neoplasms − extra-adrenal paraganglioma (chemodectomas), gastric epithelioid leiomyosarcomas (gastrointestinal stromal tumor), and pulmonary chondromas. It mainly affects young women, generally in the second or third decade.
The treatment of hamartoma is usually in the form of conservative surgery, lung sparing: Wedge resection or enucleation of peripheral lesions and sleeve resection of endobronchial lesions.
It is important to raise awareness of this lesion as it is a mimicker of primary and metastatic lung tumors, both clinically and radiologically. Also the majority of PHs show slow growth, however, it is important to recognize that some hamartomas might increase rapidly in size and show malignant alteration.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]