1. Pulmonary hamartoma
Here are two examples of a benign lung neoplasm known as a pulmonary hamartoma. These uncommon lesions appear on chest radiograph as a "coin lesion" that has a differential diagnosis of granuloma and localized malignant neoplasm. They are firm and discreet and often have calcifications in them that also appear on radiography. Most are small (less than 2 cm).

2. Pulmonary hamartoma
The pulmonary hamartoma is seen microscopically to be composed mostly of benign cartilage on the
right that is jumbled with a fibrovascular stroma and scattered bronchial glands on the left. A
hamartoma is a neoplasm in an organ that is composed of tissue elements normally found at that site,
but growing in a haphazard mass.

3. Early bronchial carcinoma
Squamous cell carcinoma: Note whitish endobronchial obstructive mass.

4. Early bronchial carcinoma
This is a fairly small carcinoma which has arisen in a bronchus blue (arrow), and then invaded into surrounding lung tissue; tumor obstructing bronchus

5. Bronchiectasis complicating bronchial carcinoma
Irregular pale growth which obstructs the lower lobe bronchus producing collapse of the lung distal to the growth and bronchiectasis.

6. Centrally located carcinoma
This pale white tumor is obstructing the right main bronchus. a squamous cell carcinoma of the lung that is arising centrally in the lung (as most squamous cell carcinomas do). Microscopy shows squamous cell carcinoma.

7. Peripheral carcinoma
Rt. This chest radiograph demonstrates a large 5 cm diameter adenocarcinoma of the right lower lobe. The bright opacity in the middle of the mass is a calcified granuloma.
Lt. Adenocarcinoma: Peripheral mass located immediately under visceral pleura, with pleural retraction.

8. Peripheral carcinoma
Adenocarcinoma. The tumor is peripherally located and has extended to the pleura.

9. Squamous cell carcinoma G
This is a large squamous cell carcinoma in which a portion of the tumor demonstrates central cavitation (arrow), probably because the tumor outgrew its blood supply.

10. Squamous cell carcinomas
The tumor usually begin as central (hilar) masses and grow contiguously into the peripheral parenchyma and adjacent pleura

11. Well differentiated squamous cell ca WD
Above: nests of squamous cells with keratin production (arrow).
Below: the pink cytoplasm with distinct cell
borders and intercellular bridges
characteristic for a squamous cell
carcinoma are seen here at high
magnification. Such features are seen in
well-differentiated tumors (those that more
closely mimic the cell of origin).

12. Pulmonary adenocarcinoma papillary and micropapillary structures
Malignant epithelial cells forming glandular structures with mucin secretion.
papillary and micropapillary structures

13. Bronchioloalveolar ca G
Greyish-white tumor involves 2/3 of left upper lobe and 1/3 of the lower lobe. The color and distribution suggest pneumonic consolidation. Secondary tumors can peoduce the same appearance.

14. Bronchioloalveolar ca mic
The tumor is composed of columnar cells that proliferate along the framework of alveolar septae. The cells are well-differentiated.

15. Large cell undifferentiated ca
Undifferentiated large cell carcinoma. Tumor is formed by large cells growing in solid nests without evidence of glandular or squamous differentiation.

16. Small cell carcinoma lung
Arising centrally in this lung and spreading extensively is a small cell anaplastic (oat cell) carcinoma. The cut surface of this tumor has a soft, lobulated, white to tan appearance. The tumor seen here has caused obstruction of the main bronchus to left lung so that the distal lung is collapsed. Oat cell carcinomas are very aggressive and often metastasize widely before the primary tumor mass in the lung reaches a large size.

17. Small cell carcinoma lung
The tumor is composed of small cells with darkly staining oval to spindle nuclei and extremely scanty cytoplasm.

18. Bronchial carcinoid
A, Bronchial Carcinoid Tumor: Yellow intrabronchial mass (lower) has resulted in obstructive bronchiectasis
B, Histologic appearance demonstrating trabecular arrangement of small, rounded, uniform cells.

19. Whole mount of carcinoid tumor showing polypoid endobronchial growth.
Carcinoid Central
Whole mount of carcinoid tumor showing polypoid endobronchial growth.

20. Carcinoid lung
The tumor is composed of nests of uniform cells that have regular round nuclei & absent or rare mitoses

21. Atypical Carcinoid
There is typical nesting of marked pleomorphic cells. mitotic activity, and necrosis are also present elsewhere.