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Granular Cell Myoblastoma of the Bronchus: Report of 2 Cases and Review of the Literature
Granular Cell Myoblastoma of the Bronchus: Report of 2 Cases and Review of the Literature Sonny S. Oparah, M.D., a n d Valavanur A. Subramanian, M.D. ABSTRACT Granular cell myoblastoma of the bronchus is rare. Two patients are described, bringing the total reported to 44. Review of the literature shows that cough, chest pain, hemoptysis, and wheezing are frequent presenting symptoms and that distal atelectasis and recurrent or persistent pneumonitis are common roentgenographic findings. Though the histogenesis of this tumor remains controversial,most pathologists now believe that the cells have a neurogenic origin. Adequate open surgical resection is the treatment of choice.
Granular cell myoblastoma of the bronchus is rare: only 42 cases have been reported in the English literature. Endobronchial granular cell myoblastoma causes symptoms by obstruction and erosion of the bronchus. Cough, chest pain, hemoptysis, and wheezing are common presenting symptoms. Distal atelectasis, persistent or recurrent pneumonitis, and suppuration are frequent findings on chest roentgenogram, necessitating a differential diagnosis from pulmonary neoplasms and infections. Perhaps more important, because of its local invasiveness and often associated atypical hyperplasia of surface epithelium, it simulates a malignant tumor both grossly and histologically. Continuing recognition of this tumor is therefore important, and it is with this in mind that we add 2 more patients, 1 of them a 10-year-old boy.
Patient 1 A 32-year-old black woman was treated in the emergency room and outpatient clinic for recurrent episodes of "bronchial asthma" for four years prior to her admission to Boston City Hospital. On admission she was in acute respiratory distress with a productive cough, temperature From the Department of Cardiothoracic Surgery, Boston City Hospital, Boston, MA. Accepted for publication Nov 25, 1975. Address reprint requests to Dr. Subramanian, The New York Hospital-Cornell Medical Center, 525 E 68th St, New York. NY 10021.
199
of 39.5"C, bronchial wheezes over the right lung field, and tachycardia. Chest roentgenograms showed right lower lobe consolidation with basal atelectasis. The white blood cell count was 18,000 with a marked shift to the left. The hematocrit was 38%. She responded to appropriate antibiotic therapy and was discharged on bronchodilator therapy but one month later was readmitted with a temperature of 40"C, shortness of breath, and a productive cough with blood- streaked sputum. Physical examination revealed right-sided inspiratory and expiratory wheezes, dullness at the lung base, and moist rales. A chest roentgenogram showed consolidation of the basal segment of the right lower lobe (Fig 1)with collapse of the right middle and right lower lobes. The consolidation was in the same segment that had been involved at the previous admission. A selective bronchogram showed a filling defect at the lower aspect of the intermediate bronchus that completely obstructed flow of contrast material into the lower lobe bronchus (Fig 2). The middle lobe bronchus was impinged upon at its origin, as seen in the oblique view, but in the anteroposterior projection it appeared patent. Sputum cytology failed to demonstrate malignant cells. Fiberoptic bronchoscopy revealed complete occlusion of the right lower lobe and partial obstruction of the right middle lobe bronchus with a friable, lobulated, grayish, endobronchial mass. The biopsy was consistent with granular cell myoblastoma. Right lower and middle lobectomies were performed. Grossly, the surgical specimen was a 2 x2 cm soft, yellowish gray tumor that had been obstructing the right lower lobe and right middle lobe bronchi, producing atelectasis of these lobes. Microscopically the lung parenchyma showed organizing bronchopneumonia, bronchiectasis, and bronchiolectasis with peribronchiolar fibrosis. There was mucosal hyperplasia as well as metaplasia (Fig 3). Granular cell myoblastoma extended into the orifice of the right
200 The Annals of Thoracic Surgery Vol 22 No 2
August 1976
Fig 1 . (Patient 1 .) Preoperative chest roentgenogram showing atelectasis of the basal segment of the right lower lobe (arrow). Fig3. (Patient 1 . ) Cellular tumor mass th,zt had been occluding the bronchial lumen. (H&E; original magnification ~ 1 0 0 . )
Fig 2 . (Patient 1 . ) Bronchogram showing filling defect caused by tumor obstruction of the right lower lobe bronchus (arrow).
middle lobe and completely obstructed the right lower lobe orifice. The postoperative course was uneventful, and she was asymptomatic three years after the operation.
Patient 2 The patient was a 10-year-old black boy who had been well until one year prior to his admission, when his father noticed that he tired very easily when playing. Eight months prior to admission the patient had complained of a sharp anterior chest pain associated with shortness of breath. The chest roentgenogram showed a left upper lobe infiltrate. With antibiotic therapy the left upper lobe "pneumonia" improved but the infiltrate persisted. Two weeks prior to admission the patient had a recurrence of left pleuritic anterior chest pain with productive cough. He was afebrile and a chest roentgenogram showed a persistent left upper lobe infiltrate. This was unchanged after two weeks of intensive medical treatment. Skin tests for tuberculosis and fungus were negative, as were sputum smears and cultures for acid-fast bacilli. Physical examination was unremarkable except for expiratory wheezes heard over the left upper chest. A bronchogram showed extensive saccular bronchiectasis of the left upper lobe with bronchial stenosis. Fiberoptic bronchoscopy revealed total obstruction of the apical segments of the left upper lobe. The lingular
201 Case Report: Oparah and Subramanian: Granular Cell Myoblastoma of the Bronchus
segment was open but stenosed. The endobronchial surface had an injected, granular appearance with no obvious endobronchial mass. The white cell count was 7,800 with no leftward shift, and the hematocrit was 40%. A left upper lobectomy was performed. The gross specimen was a yellowish gray mass that had been partially occluding the left upper lobe bronchial lumen. Microscopically the mass was consistent with granular cell myoblastoma with mucosal squamous metaplasia and hyperplasia. The lung showed bronchiectasis, focal fibrosis, and chronic and acute inflammation. The postoperative course was uneventful, and the patient was asymptomatic three years after operation.
have had multiple lesions, an incidence of about 20%. In 2 patients the tumors occurred in the bronchial tree; the other 7 had involvement of other organs (the tongue in 1, esophagus in 1, and skin in 5). The gross appearance of the endobronchial lesions ranged from a small, ridgelike thickening of the mucosa to a sessile or pedunculated, polypoid mass that partially or completely obstructed the bronchial lumen. The size of the lesion ranged from several millimeters to 6.5 cm in diameter. The cut surface of the lesion appeared yellowish gray or pink in color. Microscopically, the typical cell of granular cell myoblastoma was a large, polygonal one with finely granular eosinophilic cytoplasm and a small, dark, vesicular nucleus. Such cells were arComment ranged in syncytial masses containing long, Granular cell myoblastoma most often occurs in fusiform cells with elongated nuclei. More than the tongue; the skin, subcutaneous tissue, and 50% had squamous metaplasia of the mucosa, breast are other common sites [231. Rare loca- and in about 40% the lesion extended through tions of this lesion are the larynx [51, trachea [ll, the entire thickness of the bronchial wall into the bronchus [4, 161, chest wall [13], back, axilla, peribronchial tissue. In only 1 case was there extremities, and anogenital region. The inci- frank pulmonary parenchymal infiltration [151. dence of the endobronchial variety is about 6% The histogenicity of this tumor remains controversial, though most pathologists and onof all granular cell myoblastomas. Review of the current literature indicates that cologists today accept a neurogenic origin [2, 8, there have been 42 recorded cases of primary 171. Primary endobronchial granular cell myoblasendobronchial granular cell myoblastoma. The 2 patients reported here bring the total number to toma is a benign lesion [6,11]. Local invasion is 44. The age range has been from 8 to 56 years not unusual, but no case of distant metastasis with an average of 37 years. The sex inci- has ever been reported. In contrast, 6% of dence has been equal. Bronchial obstruction and nonendobronchial granular cell myoblastomas erosion were the basis of the symptoms due to metastasize [221. Metastatic pulmonary granular this lesion [9]. Persistent or recurrent cough, cell myoblastoma from primary sources outside chest pain, wheezing, and hemoptysis have the thorax does not present clinically as the pribeen the most common presenting symptoms. mary endobronchial granular cell myoblastoma. Chest roentgenograms usually revealed persis- Spontaneous remission of an endobronchial tent or recurrent pulmonary infiltrates or atelec- granular cell myoblastoma has not been retasis. Prompt endoscopy and biopsy established ported, although nonendobronchial types are the diagnosis in all cases. This lesion tends to known to regress [3, 121. Surgical manipulation originate in the walls of the large bronchi. In of the primary lesion may lead to secondary im59% the right main bronchus was involved; the plantation [14]. It is worthwhile to note that left main bronchus was involved in 36% and bronchoscopic removal of endobronchial myoboth bronchi in 5%. Five patients had involve- blastoma has often been followed by recurrence, ment of the carina. In 2 of these patients the either by implantation or because of inadequate carinal lesion consisted of multiple nodules and excision of the tumor [MI. The tumor has inin 2 others it was contiguous with the lesion in vaded the entire bronchial wall in more than the main bronchus; in 1 instance there was en one-third of the cases of endobronchial granular bloc involvement of the main bronchus and ad- cell myoblastoma; in 1 patient there was actual jacent lower trachea. Nine of the 44 patients infiltration of the pulmonary parenchyma.
202 The Annals of Thoracic Surgery Vol 22 No 2 August 1976
Hence, endoscopic resection of this lesion is not the optimal treatment. At present there is no evidence to suggest that endobronchial myoblastoma is radiosensitive. Of the 2 patients in the literature who were treated with radium seeds following bronchoscopic excision, 1had recurrence six years later; there is no long-term follow-up in the second. In contrast, nine- to ten-year follow-up has failed to show recurrence in those patients treated with open resection. Follow-up has been available for 24 of the patients reported so far. Five were alive and well five to ten years after resection. Eleven patients have been followed for more than three years and are also alive and well. Hemoptysis occurred in 9 patients two years after endoscopic removal, and there have been 2 postoperative deaths. Adequate open surgical resection is the treatment of choice. This may require a lobectomy [lo], with or without sleeve resection of the bronchus [20, 221, and in some instances pneumonectomy [13, 161. Lesions occurring in the trachea may require resection and reconstruction of the involved segment [l].
References 1. Archer FL, Harrison RW, Moulder PV: Granular cell myoblastoma of the trachea and carina treated by resection and reconstruction. J Thorac Cardiovasc Surg 45:539, 1963 2. Bangle R Jr: An early granular cell myoblastoma confined within a small peripheral myelinated nerve. Cancer 6:790, 1953 3. Baraf CS, Bender 8: Multiple cutaneous granular cell myoblastomas. Arch Dermatol89:243, 1964 4. Benson WR: Granular cell tumors (myoblastomas) of the tracheobronchial tree. J Thorac Cardiovasc Surg 5217, 1966 5. Blashi SF: Myoblastoma of larynx. Ann Otol Rhino1 Laryngol68:115, 1960 6. Campbell DD Jr, Smith EP Jr, Hood RH Jr, et al: Benign granular cell myoblastoma of the bronchus: review of the literature and report of a case. Dis Chest 46:729, 1964 7. De Paola D, Medeiros JAC, Rocha G, et al: Myoblastoma multiplo di bronquio: relata a un caso con pneumonectomia. Rev Bras Cir 41:197, 1961 8 . Fischer ER, Wechsler H: Granular cell myoblastoma a misnomer: electron microscopic and histochemical evidence concerning its Schwann cell derivation and nature (granular cell schwanoma). Cancer 15:936, 1962
9. Greenberg SD, Beall AC Jr, Gonzales-Anaulo A: Granular cell myoblastoma producing bronchial obstruction. Dis Chest 44:320, 1963 10. Herbert WM, Seale RH, Samson PC: Primary granular cell myoblastoma of the bronchus: report of a case with resection. J. Thorac Surg 34:409, 1957 11. Jones ER, MacArthur AM: Benign granular cell myoblastoma of the bronchus. 13r J Surg 46:420, 1959 12. Krouse TB, Mobini J: Multifocal granular cell myoblastoma: report of a case involving trachea, stomach, and anterior abdominal wall. Arch Pathol 96:99, 1973 13. Lowbeer L: Granular cell myobllastomas of unusual locations (bronchus, breast, chest wall). Am J Pathol 29:611, 1953 14. Moscovic EA, Azar HA: Multiple granular cell tumors (myoblastoma): case report with electron microscopic observations and review of the literature. Cancer 20:2032, 1961 15. Novi I: I tumori a cellule granulose (cosiddetti “miomi mioblastici di Abrikossoff): a proposito di un raro caso di tumore a cellule granulose del polmone ad evoluzione infiltrante. Arch Ital Chir 83:333, 1958 16. Ostermiller WE, Comer TP, Barker WL: Endobronchial granular cell myoblastoma: a report of three cases and review of the literature. Ann Thorac Surg 9:143, 1970 17. Pearse AGE: The histogenesis of granular cell myoblastoma (questionable granular cell perineural fibroblastoma). J Pathol Bacteriol 62:35, 1950 18. Peterson PA Jr, Soule EH, Berriatz PE: Benign granular cell myoblastoma of the bronchus: report of two cases. J Thorac Surg 34:95, 1957 19. Stein HF: Granular cell myoblastoma of the bronchus: case report with a six-year follow-up. Am Rev Resp Dis 93:275, 1966 20. Suzuki C, Oshibe M, Magashima Y: Granular cell myoblastoma of the bronchus: report of a case with treatment by upper lobectomy and sleeve resection of the stem bronchus. J Thorac Cardiovasc Surg 61:271, 1971 21. Tamayo JL, Rojas MC: Granular cell myoblastoma (granular cell schwannoma) of the right upper bronchus coexisting with a bronchogenic carcinoma. J Thorac Cardiovasc Surg 62:268, 1971 22. Umansky C, Bullock WK: Granular cell myoblastoma of the breast. Am Surg 168:810, 1968 23. Vance SF, Hudson RP Jr: Granular cell myoblastoma: clinicopathologic study of forty-two patients. Am J Clin Pathol52:208, 1969 24. Zak F, Herdegen L, Kleint Z: Ilndobronchialni granularni pseudotumor (tzv Abrikosovuv myoblasticky myomi): u ctmaetiletcho chlapce. Cesk Pediatr 14:22, 1959 I,
v
Granular cell myoblastoma of the bronchus is rare: only 42 cases have been reported in the English literature. Endobronchial granular cell myoblastoma causes symptoms by obstruction and erosion of the bronchus. Cough, chest pain, hemoptysis, and wheezing are common presenting symptoms. Distal atelectasis, persistent or recurrent pneumonitis, and suppuration are frequent findings on chest roentgenogram, necessitating a differential diagnosis from pulmonary neoplasms and infections. Perhaps more important, because of its local invasiveness and often associated atypical hyperplasia of surface epithelium, it simulates a malignant tumor both grossly and histologically. Continuing recognition of this tumor is therefore important, and it is with this in mind that we add 2 more patients, 1 of them a 10-year-old boy.
Patient 1 A 32-year-old black woman was treated in the emergency room and outpatient clinic for recurrent episodes of "bronchial asthma" for four years prior to her admission to Boston City Hospital. On admission she was in acute respiratory distress with a productive cough, temperature From the Department of Cardiothoracic Surgery, Boston City Hospital, Boston, MA. Accepted for publication Nov 25, 1975. Address reprint requests to Dr. Subramanian, The New York Hospital-Cornell Medical Center, 525 E 68th St, New York. NY 10021.
199
of 39.5"C, bronchial wheezes over the right lung field, and tachycardia. Chest roentgenograms showed right lower lobe consolidation with basal atelectasis. The white blood cell count was 18,000 with a marked shift to the left. The hematocrit was 38%. She responded to appropriate antibiotic therapy and was discharged on bronchodilator therapy but one month later was readmitted with a temperature of 40"C, shortness of breath, and a productive cough with blood- streaked sputum. Physical examination revealed right-sided inspiratory and expiratory wheezes, dullness at the lung base, and moist rales. A chest roentgenogram showed consolidation of the basal segment of the right lower lobe (Fig 1)with collapse of the right middle and right lower lobes. The consolidation was in the same segment that had been involved at the previous admission. A selective bronchogram showed a filling defect at the lower aspect of the intermediate bronchus that completely obstructed flow of contrast material into the lower lobe bronchus (Fig 2). The middle lobe bronchus was impinged upon at its origin, as seen in the oblique view, but in the anteroposterior projection it appeared patent. Sputum cytology failed to demonstrate malignant cells. Fiberoptic bronchoscopy revealed complete occlusion of the right lower lobe and partial obstruction of the right middle lobe bronchus with a friable, lobulated, grayish, endobronchial mass. The biopsy was consistent with granular cell myoblastoma. Right lower and middle lobectomies were performed. Grossly, the surgical specimen was a 2 x2 cm soft, yellowish gray tumor that had been obstructing the right lower lobe and right middle lobe bronchi, producing atelectasis of these lobes. Microscopically the lung parenchyma showed organizing bronchopneumonia, bronchiectasis, and bronchiolectasis with peribronchiolar fibrosis. There was mucosal hyperplasia as well as metaplasia (Fig 3). Granular cell myoblastoma extended into the orifice of the right
200 The Annals of Thoracic Surgery Vol 22 No 2
August 1976
Fig 1 . (Patient 1 .) Preoperative chest roentgenogram showing atelectasis of the basal segment of the right lower lobe (arrow). Fig3. (Patient 1 . ) Cellular tumor mass th,zt had been occluding the bronchial lumen. (H&E; original magnification ~ 1 0 0 . )
Fig 2 . (Patient 1 . ) Bronchogram showing filling defect caused by tumor obstruction of the right lower lobe bronchus (arrow).
middle lobe and completely obstructed the right lower lobe orifice. The postoperative course was uneventful, and she was asymptomatic three years after the operation.
Patient 2 The patient was a 10-year-old black boy who had been well until one year prior to his admission, when his father noticed that he tired very easily when playing. Eight months prior to admission the patient had complained of a sharp anterior chest pain associated with shortness of breath. The chest roentgenogram showed a left upper lobe infiltrate. With antibiotic therapy the left upper lobe "pneumonia" improved but the infiltrate persisted. Two weeks prior to admission the patient had a recurrence of left pleuritic anterior chest pain with productive cough. He was afebrile and a chest roentgenogram showed a persistent left upper lobe infiltrate. This was unchanged after two weeks of intensive medical treatment. Skin tests for tuberculosis and fungus were negative, as were sputum smears and cultures for acid-fast bacilli. Physical examination was unremarkable except for expiratory wheezes heard over the left upper chest. A bronchogram showed extensive saccular bronchiectasis of the left upper lobe with bronchial stenosis. Fiberoptic bronchoscopy revealed total obstruction of the apical segments of the left upper lobe. The lingular
201 Case Report: Oparah and Subramanian: Granular Cell Myoblastoma of the Bronchus
segment was open but stenosed. The endobronchial surface had an injected, granular appearance with no obvious endobronchial mass. The white cell count was 7,800 with no leftward shift, and the hematocrit was 40%. A left upper lobectomy was performed. The gross specimen was a yellowish gray mass that had been partially occluding the left upper lobe bronchial lumen. Microscopically the mass was consistent with granular cell myoblastoma with mucosal squamous metaplasia and hyperplasia. The lung showed bronchiectasis, focal fibrosis, and chronic and acute inflammation. The postoperative course was uneventful, and the patient was asymptomatic three years after operation.
have had multiple lesions, an incidence of about 20%. In 2 patients the tumors occurred in the bronchial tree; the other 7 had involvement of other organs (the tongue in 1, esophagus in 1, and skin in 5). The gross appearance of the endobronchial lesions ranged from a small, ridgelike thickening of the mucosa to a sessile or pedunculated, polypoid mass that partially or completely obstructed the bronchial lumen. The size of the lesion ranged from several millimeters to 6.5 cm in diameter. The cut surface of the lesion appeared yellowish gray or pink in color. Microscopically, the typical cell of granular cell myoblastoma was a large, polygonal one with finely granular eosinophilic cytoplasm and a small, dark, vesicular nucleus. Such cells were arComment ranged in syncytial masses containing long, Granular cell myoblastoma most often occurs in fusiform cells with elongated nuclei. More than the tongue; the skin, subcutaneous tissue, and 50% had squamous metaplasia of the mucosa, breast are other common sites [231. Rare loca- and in about 40% the lesion extended through tions of this lesion are the larynx [51, trachea [ll, the entire thickness of the bronchial wall into the bronchus [4, 161, chest wall [13], back, axilla, peribronchial tissue. In only 1 case was there extremities, and anogenital region. The inci- frank pulmonary parenchymal infiltration [151. dence of the endobronchial variety is about 6% The histogenicity of this tumor remains controversial, though most pathologists and onof all granular cell myoblastomas. Review of the current literature indicates that cologists today accept a neurogenic origin [2, 8, there have been 42 recorded cases of primary 171. Primary endobronchial granular cell myoblasendobronchial granular cell myoblastoma. The 2 patients reported here bring the total number to toma is a benign lesion [6,11]. Local invasion is 44. The age range has been from 8 to 56 years not unusual, but no case of distant metastasis with an average of 37 years. The sex inci- has ever been reported. In contrast, 6% of dence has been equal. Bronchial obstruction and nonendobronchial granular cell myoblastomas erosion were the basis of the symptoms due to metastasize [221. Metastatic pulmonary granular this lesion [9]. Persistent or recurrent cough, cell myoblastoma from primary sources outside chest pain, wheezing, and hemoptysis have the thorax does not present clinically as the pribeen the most common presenting symptoms. mary endobronchial granular cell myoblastoma. Chest roentgenograms usually revealed persis- Spontaneous remission of an endobronchial tent or recurrent pulmonary infiltrates or atelec- granular cell myoblastoma has not been retasis. Prompt endoscopy and biopsy established ported, although nonendobronchial types are the diagnosis in all cases. This lesion tends to known to regress [3, 121. Surgical manipulation originate in the walls of the large bronchi. In of the primary lesion may lead to secondary im59% the right main bronchus was involved; the plantation [14]. It is worthwhile to note that left main bronchus was involved in 36% and bronchoscopic removal of endobronchial myoboth bronchi in 5%. Five patients had involve- blastoma has often been followed by recurrence, ment of the carina. In 2 of these patients the either by implantation or because of inadequate carinal lesion consisted of multiple nodules and excision of the tumor [MI. The tumor has inin 2 others it was contiguous with the lesion in vaded the entire bronchial wall in more than the main bronchus; in 1 instance there was en one-third of the cases of endobronchial granular bloc involvement of the main bronchus and ad- cell myoblastoma; in 1 patient there was actual jacent lower trachea. Nine of the 44 patients infiltration of the pulmonary parenchyma.
202 The Annals of Thoracic Surgery Vol 22 No 2 August 1976
Hence, endoscopic resection of this lesion is not the optimal treatment. At present there is no evidence to suggest that endobronchial myoblastoma is radiosensitive. Of the 2 patients in the literature who were treated with radium seeds following bronchoscopic excision, 1had recurrence six years later; there is no long-term follow-up in the second. In contrast, nine- to ten-year follow-up has failed to show recurrence in those patients treated with open resection. Follow-up has been available for 24 of the patients reported so far. Five were alive and well five to ten years after resection. Eleven patients have been followed for more than three years and are also alive and well. Hemoptysis occurred in 9 patients two years after endoscopic removal, and there have been 2 postoperative deaths. Adequate open surgical resection is the treatment of choice. This may require a lobectomy [lo], with or without sleeve resection of the bronchus [20, 221, and in some instances pneumonectomy [13, 161. Lesions occurring in the trachea may require resection and reconstruction of the involved segment [l].
References 1. Archer FL, Harrison RW, Moulder PV: Granular cell myoblastoma of the trachea and carina treated by resection and reconstruction. J Thorac Cardiovasc Surg 45:539, 1963 2. Bangle R Jr: An early granular cell myoblastoma confined within a small peripheral myelinated nerve. Cancer 6:790, 1953 3. Baraf CS, Bender 8: Multiple cutaneous granular cell myoblastomas. Arch Dermatol89:243, 1964 4. Benson WR: Granular cell tumors (myoblastomas) of the tracheobronchial tree. J Thorac Cardiovasc Surg 5217, 1966 5. Blashi SF: Myoblastoma of larynx. Ann Otol Rhino1 Laryngol68:115, 1960 6. Campbell DD Jr, Smith EP Jr, Hood RH Jr, et al: Benign granular cell myoblastoma of the bronchus: review of the literature and report of a case. Dis Chest 46:729, 1964 7. De Paola D, Medeiros JAC, Rocha G, et al: Myoblastoma multiplo di bronquio: relata a un caso con pneumonectomia. Rev Bras Cir 41:197, 1961 8 . Fischer ER, Wechsler H: Granular cell myoblastoma a misnomer: electron microscopic and histochemical evidence concerning its Schwann cell derivation and nature (granular cell schwanoma). Cancer 15:936, 1962
9. Greenberg SD, Beall AC Jr, Gonzales-Anaulo A: Granular cell myoblastoma producing bronchial obstruction. Dis Chest 44:320, 1963 10. Herbert WM, Seale RH, Samson PC: Primary granular cell myoblastoma of the bronchus: report of a case with resection. J. Thorac Surg 34:409, 1957 11. Jones ER, MacArthur AM: Benign granular cell myoblastoma of the bronchus. 13r J Surg 46:420, 1959 12. Krouse TB, Mobini J: Multifocal granular cell myoblastoma: report of a case involving trachea, stomach, and anterior abdominal wall. Arch Pathol 96:99, 1973 13. Lowbeer L: Granular cell myobllastomas of unusual locations (bronchus, breast, chest wall). Am J Pathol 29:611, 1953 14. Moscovic EA, Azar HA: Multiple granular cell tumors (myoblastoma): case report with electron microscopic observations and review of the literature. Cancer 20:2032, 1961 15. Novi I: I tumori a cellule granulose (cosiddetti “miomi mioblastici di Abrikossoff): a proposito di un raro caso di tumore a cellule granulose del polmone ad evoluzione infiltrante. Arch Ital Chir 83:333, 1958 16. Ostermiller WE, Comer TP, Barker WL: Endobronchial granular cell myoblastoma: a report of three cases and review of the literature. Ann Thorac Surg 9:143, 1970 17. Pearse AGE: The histogenesis of granular cell myoblastoma (questionable granular cell perineural fibroblastoma). J Pathol Bacteriol 62:35, 1950 18. Peterson PA Jr, Soule EH, Berriatz PE: Benign granular cell myoblastoma of the bronchus: report of two cases. J Thorac Surg 34:95, 1957 19. Stein HF: Granular cell myoblastoma of the bronchus: case report with a six-year follow-up. Am Rev Resp Dis 93:275, 1966 20. Suzuki C, Oshibe M, Magashima Y: Granular cell myoblastoma of the bronchus: report of a case with treatment by upper lobectomy and sleeve resection of the stem bronchus. J Thorac Cardiovasc Surg 61:271, 1971 21. Tamayo JL, Rojas MC: Granular cell myoblastoma (granular cell schwannoma) of the right upper bronchus coexisting with a bronchogenic carcinoma. J Thorac Cardiovasc Surg 62:268, 1971 22. Umansky C, Bullock WK: Granular cell myoblastoma of the breast. Am Surg 168:810, 1968 23. Vance SF, Hudson RP Jr: Granular cell myoblastoma: clinicopathologic study of forty-two patients. Am J Clin Pathol52:208, 1969 24. Zak F, Herdegen L, Kleint Z: Ilndobronchialni granularni pseudotumor (tzv Abrikosovuv myoblasticky myomi): u ctmaetiletcho chlapce. Cesk Pediatr 14:22, 1959 I,
v