title: Sonography: an underutilized diagnostic tool in the assessment of metastatic groin nodes.
abstract: OBJECTIVE
  To assess the diagnostic value of gray-scale sonography in differentiating benign reactive nodes from metastatic nodes in the groin.
  
  
  METHODS
  Twenty-seven patients with carcinoma of the penis, 3 patients with cutaneous melanoma, and 2 patients with squamous cell carcinoma of the lower extremity with inguinal lymphadenopathy were studied. A total of 122 nodes in the groin were examined sonographically using a 7.5-MHz probe. Sonographic features studied included lymph node size, longitudinal/transverse diameter (L/T) ratio, presence or absence of echogenic hilum, and appearance of the cortex. Pathologic confirmation was obtained via lymph node biopsy in 14 patients and groin dissection in 18 patients. Sonographic features were correlated with final pathology.
  
  
  RESULTS
  Forty-four of 122 nodes were metastatic and 78 were benign. L/T <2 had a sensitivity of 81% in the diagnosis of metastasis. Absent hilum had a sensitivity of only 68% but a specificity of 95%. An eccentric cortex was also highly specific for malignancy (96%). Presence of any sonographic feature suggestive of metastasis has a high sensitivity (95%) and negative predictive value (96%). The combination of L/T ratio <2 and absent hilum had the highest specificity (97%) combined with a high positive predictive value (93%).
  
  
  CONCLUSIONS
  Sonography is useful in the evaluation of groin nodes for metastatic disease. It can help select a suspicious lymph node for cytologic/histologic confirmation.
authors.affiliation: Department of Surgery, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry 605006, India.
authors.forename: Ravula Phani
authors.initials: RP
authors.lastname: Krishna
authors.forename: Sarath Chandra
authors.initials: SC
authors.lastname: Sistla
authors.forename: Robinson
authors.initials: R
authors.lastname: Smile
authors.forename: R
authors.initials: R
authors.lastname: Krishnan
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging / Q000473:pathology; D016009:Chi-Square Distribution; D003937:Diagnosis, Differential; D005260:Female; D006119:Groin; D006801:Humans; D008207:Lymphatic Metastasis / Q000000981:diagnostic imaging*; D008297:Male; D008545:Melanoma / Q000000981:diagnostic imaging / Q000473:pathology; D010412:Penile Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D012878:Skin Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology; D014463:Ultrasonography