Indentation in the border of a solid lung mass (thought to represent a nutrient/feeding vessel) and is suggestive of a bronchial carcinoma.

The sign is not pathognomonic of bronchial carcinoma being observed in other conditions, such as granulomatous infections or benign processes such as bronchial adenoma. The sign as a differentiating utility is limited.

History of the Rigler notch sign

1955 – Leo George Rigler (1896-1979) and E. Robert Heitzman (1927-2020) published findings of their blinded review of 132 lung films with spheroidal lung nodules. The study reviewed three radiological signs of lung nodules: calcification, cavitation and notching. The authors noted that calcification was associated with benign lesions and cavitation was indicative of malignancy. The authors describe a notch sign for the first time.

A new roentgen sign, the notching or umbilication of a border of a spheroidal nodule is described. It is best demonstrated in body-section roentgenograms. When definite, it is highly indicative of malignancy, either primary or metastatic. Wen equivocal, especially in very small lesions, it is of little value. The absence of this sign is of no significance.

Rigler and Heitzman, Radiology 1955
Rigler Notch Sign 1955 X-rays
Fig. 4. (right) Notch sign as shown by planigraphy. Planigram of large squamous-cell carcinoma with cavitation. The indentation of the inferior wall (arrow) is well shown and is fairly characteristic of the notch commonly seen in malignant nodules.
Fig. 5. Notch sign in a conventional roentgenogram. Squamous-cell carcinoma showing nodular density with notch sign on superior border (arrow). Radiology 1955

Rigler and Heitzman describe the notches pathologically and histologically.

In many histologic section of this small lesion shows an area of blood vessels surrounded by alveoli which is drawn into one side of the tumour. It is possible that the tumour has grown around this stalk, thus resembling the hilus of an organ.

Rigler and Heitzman, Radiology 1955
Rigler notch sign pathology and histology

Fig. 8. Notch sign in a hypernephroma metastasis. A. Planigram showing large nodule in lung with marked indentation on lateral border, fairly characteristic of notch sign. B. Surgical specimen showing a deep groove (arrows) in the tumor corresponding to the notch. C. Microscopic section showing alveoli and blood vessels extending into the margin of the tumor. Radiology 1955

Associated Persons

Alternative names
  • Notch Sign of Malignancy


Historical references

Eponymous term review


the names behind the name

Third year M.D. student at the University of Notre Dame Fremantle. Passionate about emergency and retrieval medicine, rural practice and clinical research

BA MA (Oxon) MBChB (Edin) FACEM FFSEM. Emergency physician, Sir Charles Gairdner Hospital.  Passion for rugby; medical history; medical education; and asynchronous learning #FOAMed evangelist. Co-founder and CTO of Life in the Fast lane | Eponyms | Books | Twitter |

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.