Other Neoplastic Lesions: Benign and Malignant



  • Histologically most cases of lung cancer are adenocarcinoma, squamous cell carcinoma, large cell undifferentiated carcinoma, and small cell carcinoma.

  • If carcinoid and atypical carcinoid tumors are added to the above-mentioned histopathologic types, 99% of all primary lung neoplasms are accounted for.

  • In addition to carcinoid tumors, this chapter will focus on benign lung tumors, as well as a variety of nonbronchogenic primary pulmonary malignancies.

    • Classification of these neoplasms is problematic because of disagreement regarding the histogenesis of these varied tumors.

    • It is easiest to just discuss these neoplasms individually.



  • Most common benign lung neoplasm

  • Arrigoni and colleagues reported on 130 benign lung tumors from Mayo Clinic and found that 100 (76.9%) were hamartomas ( Table 33-1 ).

    TABLE 33-1 ▪


    Tumor Number (%)
    Hamartoma 100 (76.9)
    Benign mesothelioma 16 (12.3)
    Xanthomatous and inflammatory pseudotumors 7 (5.4)
    Lipoma 2 (1.5)
    Leiomyoma 2 (1.5)
    Hemangioma 1 (0.8)
    Mucous gland adenoma 1 (0.8)
    Mixed tumor 1 (0.8)

    * Adapted from Arrigoni MG, Woolner LB, Bernatz PE, Miller WE, Fontana WS. Benign tumors of the lung. A ten-year experience. J Thorac Cardiovasc Surg 1970;60:589-599.

  • Pathology: These tumors are derived from peribronchial mesenchyme and are composed mostly of cartilage, connective tissue, fat, smooth muscle, and respiratory epithelium ( Fig. 33-1 ).

    Figure 33-1

    Hamartoma. It is well demarcated from the surrounding lung. Note the variegated white and yellow appearance which corresponds to the cartilage and fat.

  • Clinical presentation: Most are asymptomatic and account for 7% to 14% of pulmonary coin lesions.

    • In a review of 215 patients with hamartomas, Gjevre and associates found only 3% were symptomatic.

    • Commonly occur between the ages of 40 and 70 years, with a 2:1 to 4:1 male-to-female ratio.

  • Radiology: often solitary and can occur in any part of the lung but are more common in the periphery

    • The tumors measure from 1 to 7 cm (average 2 cm) in diameter.

    • A characteristic popcorn pattern of calcification may be present on computed tomography (CT) scan in up to 30% of cases, but some authors report a much lower incidence of calcification.

    • CT may also demonstrate fat within the lesion. Siegelman and colleagues reported fat in 50% of hamartomas ( Fig. 33-2 ).

      • The presence of fat density by high-resolution CT in a peripheral solitary lesion is strong presumptive evidence for a benign hamartoma.

      Figure 33-2

      Computed tomography scan showing a 1-cm pulmonary nodule with a central fat density ( arrow ). This lesion has an appearance consistent with a hamartoma.

  • Pathology: Malignant transformation is rare.

    • Growth is slow.

    • Needle biopsy may be diagnostic.

    • This may be useful after CT studies when the diagnosis of hamartoma is still in doubt and the patient is poor risk for surgical intervention.

  • Treatment

    • Excision should be considered if the diagnosis is in doubt.

    • Small (<2 cm) hamartomas can be observed.

    • Hamartomas larger than 2.5 cm should be considered for excision.

    • Video-assisted thoracoscopic wedge resection is the preferred treatment.

      • Segmentectomy or lobectomy may be required, and pneumonectomy should be avoided.

    • Recurrence is highly unlikely.

Inflammatory Pseudotumor

  • Numerous synonyms: histiocytoma, plasma cell granuloma, plasmacytoma, xanthoma, xanthogranuloma, xanthofibroma, and inflammatory myofibroblastic tumor.

  • Pathology: Classically considered a non-neoplastic process characterized by unregulated growth of inflammatory cells.

    • Historically, cause was unknown but thought to represent an exaggerated tissue response to injury.

    • Now thought to be of neoplastic origin with evidence of rearrangement of the anaplastic lymphoma kinase gene on chromosome 2p23.

  • Presentation: The true incidence is unknown; however, in 56,400 general thoracic surgical procedures performed at Mayo Clinic between 1946 and 1993, 23 patients (0.04%) had resection of inflammatory pseudotumors.

    • Median age 47 years (range, 5 to 77 years).

    • They are the most common benign lung tumor in children.

    • Presentation is usually with symptoms: cough, weight loss, fever, fatigue.

  • Radiology: usually appear as well-defined solitary parenchymal masses 0.5 to 36 cm in diameter; the most common size is 1 cm to 6 cm.

  • Pathology: Grossly they consist of multilobular or bosselated tumor with a rubbery surface. They commonly have a white shiny appearance due to the large amount of fibrous tissue present; however, as the number of histiocytes or xanthomatous cells increase, their color becomes more yellow due to lipid accumulation ( Fig. 33-3 ).

    Figure 33-3

    Inflammatory pseudotumor. Note the sharp demarcation from the surrounding lung. The presence of xanthoma cells imparts a yellow color, plasma cells and lymphocytes a tan color, and fibrous connective tissue a white color.

  • Treatment is complete resection to avoid local recurrence.

    • In the Mayo Clinic series, complete resection was accomplished in 18 (78%) patients. Resection required pneumonectomy in six patients, bilobectomy in one, lobectomy in six, segmentectomy in one, wedge resection in seven, and chest wall resection in two.

      • Two patients with positive margins underwent re-resection, and two have been observed without evidence of tumor growth.

      • The 5-, 8-, and 10-year survival rates were 91.3%, 91.3%, and 77.7% respectively.


  • Presentation: Rare, with only two found out of 130 benign lung tumors in the Mayo Clinic series.

    • Most are endobronchial and cause obstruction.

  • Radiology: Because of their fatty composition, CT may strongly suggest the diagnosis of endobronchial lipoma.

  • Treatment: Use bronchoscopic removal whenever possible.

    • Muraoka and associates reported on 64 cases with surgical procedures including pneumonectomy in four patients, lobectomy in 24, bilobectomy in eight, bronchotomy in four, bronchoscopic removal with Nd:YAG laser in 17, cautery in five, and a combination of laser and cautery in five.

    • Reasons for surgical resection include

      • Difficulty in obtaining a definitive diagnosis and the existence of a possible complicated malignant tumor

      • Peripheral destruction of the lung secondary to long-standing atelectasis or pneumonia

      • Extrabronchial growth or the existence of subpleural lipomatous disease

      • Technical difficulties encountered during the bronchoscopic procedure


  • Presentation:

    • Account for 1.5% to 2% of benign lung neoplasms

    • Most common in young and middle-aged women

    • Location split almost evenly between lung parenchyma and tracheobronchial

    • Peripheral lung parenchymal leiomyoma are often asymptomatic while tracheobronchial leiomyoma may cause pulmonary obstruction.

  • Radiology: On CT, there are no distinguishing features from other pulmonary nodules.

  • Pathology: Grossly, they resemble smooth muscle tumors ( Fig. 33-4 ).

    Figure 33-4

    Benign pulmonary leiomyoma. The nodule is lobulated with a typical pale white smooth muscle appearance.

  • Treatment

    • Endobronchial leiomyoma without destroyed distal lung parenchyma may be treated with endobronchial resection with or without the use of Nd:YAG laser.

    • Surgical resection is the treatment of choice for peripheral leiomyoma and those endobronchial leiomyoma with destroyed distal lung tissue.

  • Benign metastasizing leiomyoma

    • Term used for multiple (occasionally single) well-differentiated pulmonary smooth muscle nodules found almost exclusively in women, many of whom have a history of uterine leiomyoma.

    • Pathology: very bland cytologic appearance, with minimal mitosis or necrosis very similar to uterine leiomyomas.

      • Controversial term because they have hematogenously spread from benign uterine leiomyoma; this contradicts their “benign” designation.

      • Kayser and colleagues compared benign metastasizing leiomyomas with uterine leiomyomas using a variety of markers such as estrogen receptor (ER) and progesterone receptor (PR) receptors and Ki-67. They concluded that benign metastasizing leiomyomas are in reality slow-growing uterine leiomyosarcomas.

      • Takemura and colleagues believe that benign metastasizing leiomyomas could be due to multicentric benign leiomyomatous growths instead of actual metastases.

    • Treatment

      • Pulmonary resection can be considered when feasible and for establishment of diagnosis.

      • These tumors can regress following oophorectomy.

      • Because these tumors are ER- and PR-receptor positive, they may respond favorably to hormonal therapy.


  • Sclerosing hemangioma

    • Presentation: Sugio and colleagues reported sclerosing hemangioma as the 2nd most common benign lung neoplasm following hamartoma.

      • Eighty percent occur in women.

      • Most are asymptomatic.

    • Radiology: they appear as a solitary, circumscribed, homogeneous mass that occasionally is calcified.

      • They range in size from 0.4 cm to 8.0 cm, with an average of 2.8 cm.

    • Pathology: Four major histologic patterns exist: solid, papillary, sclerotic, and hemorrhagic. Most of these neoplasms exhibit combinations of these patterns.

    • Treatment: Surgical resection is the procedure of choice.

      • Miyagawa-Hayashino and colleagues have reported on 4 patients with sclerosing hemangioma and lymph node metastases.

        • Lymph node metastases were described as peribronchial, regional, and hilar.

        • Despite the presence of lymph node metastases, these authors still consider sclerosing hemangiomas to be benign.

        • Because of the possibility of lymph node metastases, a regional and hilar lymph node dissection should be done in addition to surgical resection of the sclerosing hemangioma.

    • Prognosis is excellent, and prognosis did not appear to be affected by the presence of lymph node metastases.

  • Cavernous hemangioma

    • Presentation: Extremely rare, occurring in all age groups

      • Shields and Robinson consider these to be pulmonary arteriovenous malformations (AVMs).

      • May occur in the tracheobronchial tree or in the peripheral lung parenchyma

      • Presentation may be asymptomatic or include hemoptysis, respiratory distress, or congestive heart failure.

    • Treatment

      • Endobronchial lesions are managed by Nd:YAG laser.

      • Parenchymal AVMs can be embolized with metal coils and occasionally require surgical excision.

Mucous Gland Adenoma

  • Synonyms: mucous gland cystadenoma, adenomatous polyp, and adenomas of mucous gland type

  • Presentation: Rare neoplasm that occurs in both children and adults, and is more common in women.

    • Arises in the bronchus and derived from bronchial mucus glands

    • Because of their bronchial location, patients often have symptoms secondary to obstruction or hemorrhage: cough, fever, hemoptysis, recurrent pneumonia.

  • Pathology: Grossly the tumors are soft, spherical, polypoid endobronchial nodules that are usually smaller than 2 cm in diameter but may range up to 7 cm.

    • They are more common lower or middle lobe lobar or segmental bronchi.

    • The differential diagnosis includes low-grade mucoepidermoid carcinoma.

    • Distinguishing between the two types may be difficult with small biopsies. The lack of cytologic atypia, mitoses, and necrosis aids in differentiation.

  • Treatment

    • Endobronchial resection with or without the use of Nd:YAG laser or cryotherapy if there is no distal lung destruction

    • Surgical resection is the treatment of choice for these neoplasms if there is destroyed distal lung parenchyma or there are contraindications to endoscopic resection

  • Prognosis: excellent.


  • Benign tumors composed of hyaline cartilage, which may be parenchymal or involve the cartilaginous airways.

  • Presentation:

    • Endobronchial chondromas are often associated with obstructive symptoms, are more common in men, and may be treated by endobronchial removal or surgical resection.

    • Although parenchymal chondromas are frequently asymptomatic, they are more common in women and may be associated with Carney’s triad. In fact, the presence of a pulmonary chondroma in a young woman should lead to consideration of this triad, which includes

    • Chondroma of the lung single or multiple

    • Gastrointestinal stromal tumor

    • Extra-adrenal paraganglioma

  • Treatment: repeated surgical resections of the respective tumors

    • Lung parenchymal–sparing resections are adequate for pulmonary chondromas.

  • Prognosis

    • For a single pulmonary chondroma, overall survival is excellent.

    • For patients with Carney’s triad, despite repeated resections, the development of recurrent neoplasms is common. Neoplasms that grow or cause symptoms should be resected. Carney’s triad is a chronic, persistent, indolent disease extending over a long period of follow-up. Sixteen percent of patients eventually die of the disease.

Atypical Adenomatous Hyperplasia

  • Atypical adenomatous hyperplasia (AAH) is of increasing interest because of its association with bronchoalveolar carcinoma (BAC).

  • Pathology: AAH is a focal lesion smaller than 5 mm in diameter due to proliferation of atypical bronchoalveolar cells lining centriacinar alveoli.

    • Autopsy studies have demonstrated AAH in 2% to 4% of cases.

  • Presentation: Demographic data are conflicting.

    • May be more common in women

    • May be more frequent in Japanese individuals

  • Radiology:

    • Most AAH is completely invisible; however, when visible, it may present on thin-section high-resolution CT as tiny foci of ground-glass opacification within the lung parenchyma.

    • These ground-glass features, however, are not specific to AAH.

  • Differential diagnosis is primarily with BAC.

    • Grossly, AAH is typically smaller than 5 mm in diameter and BAC is larger than 10 mm; however, size alone cannot reliably make the distinction between the two.

    • Pathology: cell population of AAH may be more heterogenous and BAC more monomorphic. Of the following histologic features, AAH rarely demonstrates more than one, whereas BAC exhibits three or more.

      • Marked cell stratification

      • High cell density, with marked overlapping of nuclei

      • Coarse nuclear chromatin and prominent nucleoli

      • True papillae or an obvious picket-fence growth pattern

      • Increase in columnar cell height in excess of those lining terminal bronchioles

    • BAC

      • There are little data on the appropriate treatment of AAH.

      • In most cases, treatment is determined by the associated lesions that may be present.

        • If a ground-glass opacity is resected and AAH is identified, then only a wedge resection with free margins is required.

        • Even for BAC, there is a growing consensus that sublobar resection may be adequate therapy.


Bronchial Adenomas

  • Describe a group of slow-growing neoplasms, most of which arise from the bronchial glands

  • Three histologic types of tumors

    • Bronchial carcinoids

    • Adenoid cystic carcinoma

    • Mucoepidermoid carcinoma

  • The term bronchial adenoma is a misnomer because these tumors are usually low-grade malignancies and not benign neoplasms as the term adenoma implies.

  • The term bronchial adenoma should be avoided whenever possible.

Carcinoid Tumors

  • History: First described by Otto Lubarsch in 1888 who identified multiple tumors in the distal ileum of two patients at autopsy.

  • Sigfried Oberndorfer in 1907 coined the term karzinoide to describe tumors with carcinoma-like features but a much more indolent behavior.

  • Pathology

  • Pulmonary carcinoids are malignant neuroendocrine tumors comprising 1% to 2% of all primary lung tumors and 85% of bronchial gland tumors.

    • Carcinoid tumors are part of the spectrum of malignant neuroendocrine tumors, which range from low-grade typical carcinoid tumors to intermediate-grade atypical carcinoid tumors to high-grade tumors, including large cell neuroendocrine carcinoma and small cell lung carcinoma.

    • Most pulmonary carcinoid tumors arise in major bronchi.

      • Ten percent in mainstem bronchi

      • Seventy-five percent in lobar bronchi

      • Fifteen percent in the lung periphery that is segmental bronchi and distal

    • Frequently have a large endobronchial component with a fleshy smooth polypoid mass protruding into the bronchial lumen ( Fig. 33-5 ). The cut surface may appear tan-yellow or red depending on the extent of vascularity.

Jun 24, 2019 | Posted by in CARDIAC SURGERY | Comments Off on Other Neoplastic Lesions: Benign and Malignant
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