Primary pulmonary rhabdomyosarcoma can be divided into two groups: tumour in the normal lung, and tumor in cystic lesions of the lung.

These rare tumours of lung may present within normal lung parenchyma as solid mass or as endobronchial lesions with symptoms of pulmonary obstruction.  Image Link

Histologically, both alveolar or embryonal variants are seen. Cytoplasmic cross-striations and immunohistochemical stains are of great value for diagnosis.

Primary pulmonary rhabdomyosarcoma is a rare entity and the histological differential diagnosis can be difficult. We report on a 43-year old female patient, smoker (25 pack-years), in whom a large solitary brain metastasis was diagnosed and enucleated. Histological examination revealed a typical small cell carcinoma and histological examination of biopsies obtained from a tumor in the left upper lobe of the lung was compatible with a small cell carcinoma. Despite chemotherapy there was a progressive tumor growth. Bronchial biopsies again showed a small cell tumor, although immunohistochemistry proved it to be a pleomorphic rhabdomyosarcoma. Due to the progressive tumor growth with necrosis and superinfection and a lack of further metastases lobectomy of the left upper lobe was performed, complicated by postoperative pleural empyema, limiting the possibilities of adjuvant therapy. Early relapse occurred with pleural, pulmonary, chest wall and spinal metastases. Laminectomy and extirpation of the spinal metastases, local radiotherapy and chemotherapy with iphosphamide and doxorubicine led to partial remission and clinical improvement for few months only. The patient died from metastatic primary rhabdomyosarcoma of the lung. This rare tumor mimicked small cell lung cancer. Appraisal of the atypical clinical course and a close dialogue between pathologists and clinicians enabled the correct diagnosis.

Primary rhabdomyosarcoma of the lung arising over cystic pulmonary adenomatoid malformation. Pediatr Hematol Oncol. 2005 Sep;22(6):525-9.

The authors report the case of a 2-year-old girl with pulmonary cystic adenomatoid malformation type II who presented with a mass on the lower lobe of the left lung. Resection and histological examination revealed pleomorphic rhabdomyosarcoma. Chemotherapy and radiotherapy followed the operation and the girl is alive and in perfect condition 10 years after the operation. The literature on primary rhabdomyosarcoma of the lung in children is reviewed.

Metastatic germ cell tumor of the lung masquerading as primary rhabdomyosarcoma.Pathol Int. 2005 Oct;55(10):649-54.

Two years after testicular resection was carried out in a 40-year-old man that revealed mixed germ cell tumor of more than one histological type (seminoma, embryonal cell carcinoma, and yolk sac tumor), he presented with an asymptomatic pulmonary nodule in his left lower lobe. Video-assisted thoracoscopic partial resection of the tumor revealed a 24 x 20 mm teratoma with somatic-type malignancy in which pleomorphic rhabdomyosarcoma was a major element. One year later, asymptomatic tumor recurrence occurred at both edges of the stapler line as 22 x 20 mm and 10 x 5 mm nodules composed only of pleomorphic rhabdomyosarcoma. Throughout the course there was no abdominal lymph node swelling detected by computed tomography (CT) and tumor markers were normal. Adjuvant chemotherapy was started after the tumor recurrence. Currently, the patient is still undergoing chemotherapy 5 months after the tumor recurrence. In conclusion, despite the fact that primary pulmonary rhabdromyosarcoma is a rare neoplasm, metastatic pulmonary germ cell tumor with somatic-type malignancy showing predominantly rhabdomyosarcomatous differentiation should be considered in the differential diagnosis of such lesions of the lung.

Primary pulmonary rhabdomyosarcoma arising within cystic adenomatoid malformation: a case report and review of the literature.J Pediatr Surg. 2001 Jul;36(7):1062-5

The current report describes a 13-month-old boy with primary pulmonary rhabdomyosarcoma (RMS) that originated within a congenital cystic adenomatoid malformation (CCAM). To the best of our knowledge, he is the youngest patient of all primary pulmonary RMS cases reported in the English-language literature. The tumor, localized in left upper lobe, was removed completely, and histologic examination showed embryonal subtype. Postoperative systemic chemotherapy was carried out. Recent evaluation 15 months after resection has not identified any residual or recurrent disease. Primary pulmonary RMS, although very rare in the pediatric age group, should be considered in young patients with solitary pulmonary masses and associated cystic lesions.

Embryonal rhabdomyosarcoma of the lung arising in cystic adenomatoid malformation: case report and review of the literature. J Pediatr Surg. 1997 Sep;32(9):1381-3

Rhabdomyosarcoma (RMS) of the lung is a very rare lesion, but the association with cystic adenomatoid malformation (CCAM) is unlikely to be a coincidence. Although the etiologic factors predisposing infants and children to pulmonary neoplasms are unknown, pulmonary developmental abnormalities may play a pathogenetic role. A case of embryonal pulmonary RMS is described, which was discovered within a congenital CCAM in a 22-month-old child. The hypothesis regarding histogenesis of this neoplasm are also briefly discussed. Because of the risk of malignant change, early removal of the congenital cystic lesions of the lung is advisable.

Alveolar rhabdomyosarcoma of the lung in a child.J Pediatr Surg. 1995 Nov;30(11):1607-8.

The case of a 22-month-old boy with alveolar rhabdomyosarcoma of the lung is presented. Brain metastasis and recurrence of the right pulmonary hilum and parietal pleura developed 6, 11, and 24 months (respectively) after tumor resection. Chemotherapy and radiotherapy were effective. Neuron-specific enolase was very helpful in detecting metastasis and disease recurrence. Primary pulmonary rhabdomyosarcoma can be divided into two groups: tumor in the normal lung, and tumor in cystic lesions of the lung.