Radiologic sign in psoriatic arthritis
Pencil-in-cup is a radiologic sign indicating a deformity where fingers have the appearance of a pencil lying in a cup.[ 1] [ 2] [ 3] This sign is classically seen in psoriatic arthritis, but it is also reported in systemic sclerosis and rheumatoid arthritis.[ 4]
^ Mochizuki, Takeshi; Ikari, Katsunori; Okazaki, Ken (4 November 2018). "Delayed Diagnosis of Psoriatic Arthritis Mutilans due to Arthritis Prior to Skin Lesion" . Case Reports in Rheumatology . 2018 : e4216938. doi :10.1155/2018/4216938 . PMC 6247716 . PMID 30533239 .
^ Laasonen, Leena; Lindqvist, Ulla; Iversen, Lars; Ejstrup, Leif; Jonmundsson, Thorarinn; Ståhle, Mona; Gudbjornsson, Bjorn (1 April 2020). "Radiographic scoring systems for psoriatic arthritis are insufficient for psoriatic arthritis mutilans: results from the Nordic PAM Study" . Acta Radiologica Open . 9 (4): 2058460120920797. doi :10.1177/2058460120920797 . ISSN 2058-4601 . PMC 7218277 . PMID 32426163 .
^ Laasonen, Leena; Gudbjornsson, Björn; Ejstrup, Leif; Iversen, Lars; Ternowitz, Thomas; Ståhle, Mona; Lindqvist, Ulla (6 July 2015). "Radiographic development during three decades in a patient with psoriatic arthritis mutilans" . Acta Radiologica Open . 4 (7): 2058460115588098. doi :10.1177/2058460115588098 . ISSN 2058-4601 . PMC 4548743 . PMID 26346445 .
^ Ramakrishnan, S.; Das, S. K.; Mishra, K. (May 2001). "Systemic sclerosis with pencil-in-cup deformity". Rheumatology . 40 (5): 594–595. doi :10.1093/rheumatology/40.5.594 . PMID 11371676 .