Ann Thorac Surg 2004;77:1096-1098
© 2004 The Society of Thoracic Surgeons
Case report
Peripheral intrapulmonary lymph node metastases of non-small-cell lung cancer
Souheil Boubia, MDa,
Françoise Lepimpec Barthes, MDa,
Claire Danel, MDa,
Marc Riquet, MD, PhDa*
a Departments of Thoracic Surgery and Pathology, Georges Pompidou European Hospital, Paris, France
Accepted for publication April 9, 2003.
* Address reprint requests to Dr Riquet, Service de Chirurgie Thoracique, Hôpital Européen Georges Pompidou, 20-40 Rue Leblanc, 75015 Paris, France
e-mail: marc.riquet{at}hop.egp.ap-hop-paris.fr
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Abstract
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Since the development and progress of computed tomographic imaging, peripheral intrapulmonary lymph nodes (IPLNs) have become increasingly described and well-known entities. Intrapulmonary lymph nodes may appear as a solitary pulmonary nodular shadow mimicking a non-small-cell lung cancer (NSCLC) or as multiple nodules masquerading as carcinoma metastases. We describe a case in which IPLNs presented as a clinical "nodular" T4 N0 NSCLC that finally proved to be a pathologic T2 N1 NSCLC, thus raising new questions on this entity.
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Introduction
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Intrapulmonary lymph nodes (IPLNs) are located distal to the fourth-order bronchi. Trapnell [1] demonstrated IPLNs in 7% of postmortem lungs by injecting contrast medium into pleural lymphatic vessels, which were detected by plain radiography in less than 1% of cases. The increasing availability of sensitive radiographic techniques has increased the frequency of detection of these nodes. Intrapulmonary lymph nodes may appear as a solitary pulmonary nodular shadow mimicking a non-small-cell lung cancer (NSCLC) [2] or as multiple nodules masquerading as carcinoma metastases [3, 4]. We observed a case presenting as a clinical "nodular" T4 N0 NSCLC [5] that proved to be a pathologic T2N1 NSCLC. Such a presentation of IPLNs raises questions on the role this entity may play in NSCLC lymphatic spread.
A 51-year-old woman who was a heavy smoker with a past medical history of tuberculosis primoinfection underwent a chest roentgenogram demonstrating an excavated opacity of the right lower lobe (RLL) with a satellite nodule. Bronchoscopy demonstrated hypervascularization of the RLL apical bronchus suggestive of sequelae of tuberculosis. Distal biopsy results were negative, and aspiration results were positive for carcinomatous cells suggestive of squamous cell carcinoma.
A chest computed tomographic (CT) scan demonstrated a necrosed tumor with two satellite nodules (Fig 1) and no lymph node involvement (clinical T4 N0). Extension assessment was negative and surgical treatment was scheduled. A right lower lobectomy with mediastinal lymph node dissection was performed.
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Fig 1. Chest tomodensitometry. (a) Posterior bilobar tumor and shadow of an anterior satellite nodule. (b) Neighboring slide demonstrating the two nearby satellite nodules.
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A histologic examination of the resected material demonstrated the main lesion to be a squamous cell carcinoma. The first nodule, distant by about 1 cm from the main lesion, appeared as a metastasis (Fig 2). The second nodule was approximately 2 cm from the main lesion and corresponded to an IPLN with carcinoma metastasis (Fig 3a). The first nodule was reexamined and was in fact also a metastasis developed in an IPLN, with the destruction of the lymph node architecture, capsular effraction, and lymphatic carcinomatous emboli (Fig 3b); remnants of the lymph nodes had escaped the first examination, and the NSCLC was reclassified as T2 N1.
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Fig 2. Metastatic satellite nodule with carcinomatous lymphangitis (asterisks) (hematoxylin & eosin stain, magnification x200).
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Fig 3. (a) Intrapulmonary lymph node with microscopic metastasis (asterisks) among lymphoid follicles (hematoxylin & eosin stain, magnification x100). (b) On the new section, malignant cells appear to have developed within another intrapulmonary lymph node (hematoxylin & eosin stain, magnification x200).
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Comment
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The existence of satellite nodules within the ipsilateral primary lobe of the lung is classified as T4, and thus the NSCLC is stage IIIB [5]. Stage IIIB NSCLCs are poor candidates for surgical intervention. The treatment of patients with multiple intrapulmonary lesions remains controversial; one lesion may be a metastasis of the other, or either lesion may be benign or malignant [6]. However, it has been demonstrated that the existence of a solitary intrapulmonary sublesion should not preclude surgical treatment, unless surgical intervention is contraindicated because of other clinical or radiologic findings [6], which was the case in our observation, initially classified as a T4 N0 NSCLC.
Intrapulmonary lymph nodes may represent the pathologic diagnosis in up to 46.2% of small pulmonary nodules demonstrated by chest CT scans [2]. Most IPLNs may be considered to be acquired, highly organized lymphoid nodules formed along interlobular lymphatic drainage routes [7]. Seventy-two percent are located in the lower-lobes [2]. Thirty-five percent are multiple nodes [7].
In our patient, the lower-lobe location of two IPLNs was therefore not surprising. The originality of this case is that both IPLNs were metastatic. In 1965, Greenfield and Jelaso [8] reported two peripheral left lower-lobe nodules that at surgical intervention appeared to be IPLNs, and microscopic study revealed undifferentiated squamous cell carcinoma in one. Five enlarged lymph nodes were palpated in the left mediastinum, and one of these examined by frozen section also showed metastatic squamous cell carcinoma. However, no primary lung cancer was found in the left lung of the patient.
In our patient, a primary NSCLC was present. The IPLN in proximity to the tumor was initially interpreted as a satellite nodule. In fact, a metastatic IPLN due to the bulky involvement of its structure may be misinterpreted as a satellite nodule, suggesting the need for careful evaluation and interpretation of all satellite nodules in the area. For improved patient staging, we suggest that when a nodule is present in the lobe affected by cancer, one should rule out possible metastatic IPLNs.
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References
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- Trapnell D.H. Recognition and incidence of intrapulmonary lymph nodes. Thorax 1964;19:44-50.
- Yokomise H., Mizuno H., Ike O., Wada H., Hitomi S., Itoh H. Importance of intrapulmonary lymph nodes in the differential diagnosis of small pulmonary nodular shadows. Chest 1998;113:703-706.[Abstract/Free Full Text]
- Kolosseus R.C., Temes R.T., Feddersen R.M., Williamson M., Smith A.Y. Intrapulmonary lymph nodes masquerading as renal cell carcinoma metastases. Urology 1995;46:249-250.[Medline]
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- Mountain C.F. Revisions in the international system for staging lung cancer. Chest 1997;111:1710-1717.[Abstract/Free Full Text]
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- Greenfield H., Jelaso D.V. Peripheral intrapulmonary lymph node metastasis. Br J Radiol 1965;38:955-956.[Medline]
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Abstract
Introduction
