Cartilaginous Hamartoma

Key Facts

Terminology

Benign mesenchymoma

Clinical Issues

Intrapulmonary coin lesion of variable size
Central or peripheral tumor
Complete surgical resection
Excellent prognosis

Macroscopic Features

Well-circumscribed lesion
Firm with mucoid and cartilaginous areas
Usually a single lesion
Rarely hamartomas may present as multiple intrapulmonary lesions

Top Differential Diagnoses

Bronchial chondromas
- Do not show invaginations of respiratory epithelium
- May be associated with other conditions, such as gastric smooth muscle tumors
Pleomorphic adenoma
- Shows presence of epithelial component that immunophenotypically is myoepithelial
- PA in the lung rarely will show mature cartilage
- Also lacks presence of invaginations of respiratory epithelium
Chondrosarcoma
- Will display more cellular atypia
- Does not have admixture of adipose tissue
- Lacks presence of invaginations of respiratory epithelium

Gross photograph shows a well-circumscribed intrapulmonary tumor, slightly lobulated with a cartilaginous appearance. These features are classical for cartilaginous hamartoma.

CH shows areas of well-formed cartilage

, adipose tissue

, and invaginated respiratory epithelium

. These features are characteristic of hamartoma.

TERMINOLOGY

Abbreviations

Cartilaginous hamartoma (CH)

Synonyms

Benign mesenchymoma

Definitions

Benign mesenchymal tumor of the lung

ETIOLOGY/PATHOGENESIS

Pathogenesis

It is not clear whether CH represents a true tumor or hamartomatous lesion
- Thus, both terms, benign mesenchymoma and hamartoma, have been used interchangeably

CLINICAL ISSUES

Presentation

Intrapulmonary coin lesion of variable size
Central or peripheral tumor

Treatment

Surgical approaches
- Complete surgical resection

Prognosis

Excellent prognosis; cured by simple excision

MACROSCOPIC FEATURES

General Features

Well-circumscribed lesion
Firm with mucoid and cartilaginous areas
Usually solitary
Rarely hamartomas may present as multiple intrapulmonary lesions

MICROSCOPIC PATHOLOGY

Histologic Features

Mature cartilage
Adipose tissue
Myxoid stroma
Invaginations of respiratory epithelium

Predominant Pattern/Injury Type

Chondromyxoid

Predominant Cell/Compartment Type

Cartilaginous

DIFFERENTIAL DIAGNOSIS

Bronchial Chondroma

Does not show invaginations of respiratory epithelium
Branchial chondroma rarely will show additional adipose tissue
May be associated with other conditions, such as gastric smooth muscle tumors

Pleomorphic Adenoma (PA)

Shows presence of epithelial component that immunophenotypically is myoepithelial
PA in the lung rarely shows mature cartilage
Also lacks presence of invaginations of respiratory epithelium

Chondrosarcoma, Primary or Metastatic