Other Neoplastic Lesions: Benign and Malignant




OTHER NEOPLASTIC LESIONS


Introduction





  • 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.






BENIGN NEOPLASMS OF THE LUNG


Hamartoma





  • 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 ▪

    BENIGN LUNG TUMORS AND THEIR INCIDENCE *































    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.





Lipoma





  • 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





Leiomyoma





  • 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.





Hemangioma





  • 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.



Chondroma





  • 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.








MALIGNANT NEOPLASMS OF THE LUNG


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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