The Octopus Sign—A New HRCT Sign in Pulmonary Langerhans Cell Histiocytosis
Alexander Poellinger,
Sabina Berezowska,
Jeffrey Leon Myers,
Adrian Huber,
Manuela Funke-Chambour,
Sabina Guler,
Thomas Geiser,
Sergio Harari,
Antonella Caminati,
Maurizio Zompatori,
Nicola Sverzellati
Affiliations
Alexander Poellinger
Department of Diagnostic, Interventional and Pediatric Radiology, University Hospital of Bern, University of Bern, 3010 Bern, Switzerland
Sabina Berezowska
Department of Laboratory Medicine and Pathology, Institute of Pathology, Lausanne University Hospital, University of Lausanne, Rue du Bugnon 25, 1011 Lausanne, Switzerland
Jeffrey Leon Myers
Department of Pathology, University of Michigan Hospital, Ann Arbor, MI 48109, USA
Adrian Huber
Department of Diagnostic, Interventional and Pediatric Radiology, University Hospital of Bern, University of Bern, 3010 Bern, Switzerland
Manuela Funke-Chambour
Department of Pulmonary Medicine, University Hospital of Bern, University of Bern, 3010 Bern, Switzerland
Sabina Guler
Department of Pulmonary Medicine, University Hospital of Bern, University of Bern, 3010 Bern, Switzerland
Thomas Geiser
Department of Pulmonary Medicine, University Hospital of Bern, University of Bern, 3010 Bern, Switzerland
Sergio Harari
Department of Medicine, Division of Internal Medicine, Ospedale San Giuseppe MultiMedica IRCCS, University of Milan, 20133 Milan, Italy
Antonella Caminati
U.O. di Pneumologia e Terapia Semi-Intensiva Respiratoria, Servizio di Fisiopatologia Respiratoria e Emodinamica Polmonare, Ospedale San Giuseppe, MultiMedica IRCCS, University of Milan, 20133 Milan, Italy
Maurizio Zompatori
Department of Medicine, Division of Internal Medicine, Ospedale San Giuseppe MultiMedica IRCCS, University of Milan, 20133 Milan, Italy
Nicola Sverzellati
Scienze Radiologiche, Department of Medicine and Surgery, Padiglione Barbieri, University of Parma, V. Gramsci 14, 43124 Parma, Italy
Background: Fibrosis in pulmonary Langerhans cell histiocytosis (PLCH) histologically comprises a central scar with septal strands and associated airspace enlargement that produce an octopus-like appearance. The purpose of this study was to identify the octopus sign on high-resolution computed tomography (HRCT) images to determine its frequency and distribution across stages of the disease. Methods: Fifty-seven patients with confirmed PLCH were included. Two experienced chest radiologists assessed disease stages as early, intermediate, or late, as well as the lung parenchyma for nodular, cystic, or fibrotic changes and for the presence of the octopus sign. Statistical analysis included Cohen’s kappa for interrater agreement and Fisher’s exact test for the frequency of the octopus sign. Results: Interobserver agreement was substantial for the octopus sign (kappa = 0.747). Significant differences in distribution of the octopus sign between stages 2 and 3 were found with more frequent octopus signs in stage 2 and fewer in stage 3. In addition, we only found the octopus sign in cases of nodular und cystic lung disease. Conclusions: The octopus sign in PLCH can be identified not only on histological images, but also on HRCT images. Its radiological presence seems to depend on the stage of PLCH.
