CT of the axilla: normal anatomy and pathology

Imaging findings of variable axillary mass and axillary lymphadenopathy

The axilla is a triangular space that contains mesenchymal tissues such as fat, vessels, nerves and lymph nodes, from which various diseases can develop. This article describes axillary masses and axillary lymphadenopathies using imaging findings from techniques such as ultrasonography, mammography, computed tomography and magnetic resonance imaging. Awareness of the characteristic imaging findings of disease entities that cause axillary masses and various axillary lymphadenopathies will help in the accurate diagnosis of axillary lesions.

Sonographic findings of axillary masses: what can be imaged in this space?

The diagnosis of axillary masses can be challenging because various tumors can develop in parts of the axilla other than lymph nodes, even though we frequently encounter axillary masses in daily practice. These lesions include soft tissue masses associated with nontumorous conditions (accessory breast tissue and chronic granulomatous inflammation) and benign and malignant tumorous conditions (lipomas, epidermal inclusion cysts, lymphangiomas, fibroadenomas, schwannomas, malignant neuroendocrine tumors, and lymph node-associated diseases). In this pictorial essay, we display commonly encountered sonographic findings of various axillary lesions to assist in the differential diagnosis of axillary masses.

Imaging-pathologic correlation of diseases in the axilla

OBJECTIVE

This article reviews the imaging and histopathologic findings of various axillary diseases and suggests management guidelines for radiologists based on imaging findings with clinical correlation.

CONCLUSION

Although axillary diseases may reveal nonspecific imaging findings, a knowledge of the characteristic radiologic manifestations of specific diseases according to anatomic origin (nodal, accessory breast, adipocytic, fibrous, nerve, vascular, stromal, and dermal) and postsurgical lesions aids in establishing an appropriate differential diagnosis and determining whether intervention is necessary.

Sonography of axillary masses: what should be considered other than the lymph nodes?

OBJECTIVE

The purpose of this study was to review the sonographic findings of various axillary masses other than lymph nodes in correlation with other imaging and pathologic findings.

METHODS

From a sonographic database, we collected interesting cases of axillary masses with pathologic or other imaging corroboration from the last 10 years.

RESULTS

Images of various soft tissue masses were reviewed. They included masses associated with accessory breasts (fibroadenomas, hamartomas, fat necrosis, and cancer arising from axillary breasts), other soft tissue masses (lipomas, schwannomas, hemangiomas, fibromatosis, epidermoid cysts, and malignant fibrous histiocytomas), and complications presenting as masses after axillary lymph node dissection (seromas, hematomas, suture granulomas, pseudoaneurysms, and lymphangiectasia).

CONCLUSIONS

Awareness of the characteristic sonographic findings of various disease entities that cause axillary masses will help in the correct diagnosis of axillary masses.

Technique for axillary radiotherapy using computer-assisted planning for high-risk skin cancer

High-risk skin cancer arising on the upper limb or trunk can cause axillary nodal metastases. Previous studies have shown that axillary radiotherapy improves regional control. There is little published work on technique. Technique standardization is important in quality assurance and comparison of results especially for trials. Our technique, planned with CT assistance, is presented. To assess efficacy, an audit of patients treated in our institution over a 15-month period was conducted. Of 24 patients treated, 13 were treated with radical intent, 11 with this technique. With a follow up of over 2 years, the technique had more than a 90% (10/11) regional control in this radical group. Both of the radical patients who were not treated according to the technique had regional failure. One case of late toxicity was found, of asymptomatic lymphoedema in a radically treated patient. This technique for axillary radiotherapy for regional control of skin cancer is acceptable in terms of disease control and toxicity as validated by audit at 2 years.

Acetabular Fractures Revisited:Part 2, A New CT-Based Classification

OBJECTIVE

The objective of this investigation was to provide a new CT-based classification of acetabular fractures.

MATERIALS AND METHODS

The axial CT scans of 112 randomly selected acetabular fractures in patients admitted to a level 1 trauma center between January 1998 and December 2000 were analyzed by an experienced orthopedic trauma surgeon and two experienced emergency radiologists. When available, 3D reformatted images were analyzed as well. The fracture pattern for each acetabular fracture, with respect to column walls and extension beyond the acetabulum, when present, was recorded. Fracture comminution was not a defining characteristic.

RESULTS

Analysis of the 112 acetabular fracture patterns showed that each fracture fell into one of four broad categories. Category 0 included wall fractures only. Category I included acetabular fractures limited to a single (anterior or posterior) column. Category II fractures included those involving both the anterior and posterior columns; category II fractures were further subdivided into those with no fracture extension beyond the acetabulum, those with superior or inferior extension, and those with both superior and inferior extensions beyond the acetabulum. Category III fractures included only the "floating" acetabulum, which is defined as an acetabular fracture in which the acetabulum is separated from the axial skeleton both anteriorly and posteriorly.

CONCLUSION

The axial CT display of acetabular fracture patterns provides a basis for a classification of acetabular fractures that is simple, unambiguous, readily understood by both radiologists and orthopedic surgeons and provides clear direction for both diagnosis and surgical treatment planning. Category and subcategory fracture specificity creates a mechanism for intra- and interdepartmental postoperative assessment of any of the individual acetabular fracture types.

Axillary lymph node metastases of bronchogenic carcinoma

BACKGROUND

Metastasis of bronchogenic carcinoma to axillary lymph nodes is rare. The pathways and possible significance of axillary lymph node metastasis from bronchogenic carcinoma were investigated.

METHODS

Seventeen patients with probable axillary lymph node metastases from bronchogenic carcinoma were identified by computed tomography. There were 15 nonsmall cell lung cancers and 2 small cell lung cancers. Axillary lymph node metastasis was proven by biopsy in six cases. Metastases were presumed because of an increase in the size of axillary lymph nodes compared with prior studies in six patients and enlarged axillary lymph nodes associated with biopsy-proven ipsilateral supraclavicular lymph node metastasis in five patients.

RESULTS

Four of 10 right-sided lung cancers had ipsilateral and six had contralateral axillary lymph node metastases. Six of seven left-sided cancers had ipsilateral and one had contralateral axillary lymph node metastases. Patients with ipsilateral lymph node disease had chest wall involvement and/or supraclavicular and mediastinal lymph node metastases. All seven patients with contralateral axillary lymph node metastases had supraclavicular and/or mediastinal lymph node metastases.

CONCLUSION

Bronchogenic carcinoma may involve ipsilateral axillary lymph nodes via either chest wall invasion or retrograde spread from supraclavicular lymph nodes. Contralateral axillary lymph node involvement requires involvement of contralateral mediastinal and supraclavicular lymph nodes with retrograde spread to the axillary lymph nodes.

The role of computed tomography in the investigation of recurrent axillary disease in patients with carcinoma of the breast

Carcinoma of the breast commonly recurs in the axilla. A nodal mass may be palpable and computed tomography (CT) is frequently requested in order to differentiate recurrent tumour from the longer term effects of surgery and radiotherapy. We have reviewed the CT scans of 35 such patients referred consecutively to our CT unit. CT only detected the presence of recurrent tumour in one patient in whom a mass could not be palpated. This patient had a previously irradiated 'wooden' axilla making clinical examination impossible. CT failed to diagnose recurrence in two patients; one with disease in normal sized nodes and the other with axillary vein thrombosis. We conclude that CT of the axilla only appears to be of value when the axilla is impossible to palpate due to previous treatment. The key to the diagnosis of axillary tumour recurrence is careful palpation supplemented by aspiration cytology of any mass. When no mass is evident on clinical examination, CT is unlikely to demonstrate disease.