Cytodiagnosis of SynovialChondromatosis of Knee JointFrom an Aspirate

Dear Dr. Bedrossian:Synovial chondromatosis is a rare, benign disorder of the

joint. The condition is mostly monoarticular, of unknownorigin, and frequently involves the knee, shoulder, and hip,and less frequently the temporomandibular joint.1–7 It ischaracterized by metaplasia of synovium with formation offoci of cellular hyaline cartilage which may calcify andrarely detach from the synovium in joint space as loosebodies. Although the diagnosis of synovial chondromatosisafter histopathological examination of tissue is known, itscytodiagnosis from aspirated fluid from a joint space to ourknowledge has not been reported. In this communication, wedescribe a case in which the cytodiagnosis of chondromato-sis could be rendered on examination of aspirated fluid fromthe knee joint and which correlated with the radiologicalimpression.

A 72-yr-old white female with long-standing history ofpain in the right knee, symptomatically managed by anti-inflammatory and analgesic drugs, started having constantpain for the last few months following a fall. Plain X-ray ofthe knee showed punctate calcifications in the meniscusindicative of chondromatosis as well as degenerative changeswithout any loose bodies. A small effusion in the knee jointwas also noted. This was aspirated and sent for cytologicevaluation. An arthroscopic lavage was done and injectionof steroid was given with some improvement in the symp-toms.

For cytologic study, the aspirate sample from the knee inthe syringe and needle was immediately washed in acytology container in which 30% ethyl alcohol in physi-ologic saline was present. This was accomplished by with-drawing the 30% ethyl alcohol in the syringe barrel, andwith the needle attached, flushing the contents back into thecytology container and repeating this procedure three timesfor maximum recovery of aspirated material. From thesewashings, cytologic preparations were made on membranefilter (size 22 mm; pore size 3 µm). The staining was done bythe Papanicolaou method. Additionally, a cell block from theremainder of aspirate washings was made after centrifuga-tion. The cell button was fixed in 10% neutral buffered

formalin, processed, and embedded, and sections were cut at5 µm and stained with hematoxylin-eosin (H&E). Cytohisto-logic study of the stained filter preparation and cell blockshowed mildly atypical chondrocytes in cellular hyalinecartilage and focal calcification (Fig. 1). No malignantchanges or ossification were noted.

According to Jaffe,8 synovial chondromatosis is a condi-tion in which foci of cartilage develop in the synovialmembrane of a joint through metaplasia of sublining connec-tive tissue. This may have been the cause in the casepresented. The case also is of interest because a cytodiagno-sis could be made on the aspirate sample which substanti-ated the radiologic impression.

Raj K. Gupta,M.D., F.I.A.C.Sarla Naran,B.S.C., C.M.I.A.C.Y.K. Cheung,F.R.C.R., F.R.A.C.R.Departments of Cytology and RadiologyWellington Hospital and School of MedicineWellington, New Zealand

Fig. 1. Filter preparation of the aspirate showing features of chondromato-sis characterized by mildly atypical cartilaginous cells with focal depositsof calcium (Papanicolaou,3250).

r 1999 WILEY-LISS, INC. Diagnostic Cytopathology, Vol 20, No 2 111

References1. Jeffreys TE. Synovial chondromatosis. J Bone Jt Surg 1967;49:530–534.2. Milgram JW. Synovial osteochondromatosis. A histopathological study

of thirty cases. J Bone Jt Surg 1977;59:792–801.3. Axhausen G. Pathologic und therapie des kiefergelenkes. Fortschr

Zahnheilkunde 1933;9:171–186.4. Blankestijn J, Panders AK, Vermey A, Schepbier AJJA. Synovial

chondromatosis of the temporomandibular joint. Report of three casesand review of the literature. Cancer 1985;55:479–485.

5. Forssell K. Happonen RP, Forssell H. Synovial chondromatosis oftemporomandibular joint. Report of a case and review of the literature.Int J Oral Maxillofac Surg 1988;17:237–241.

6. Von Arx DP, Simpson MT, Batman P. Synovial chondromatosis of thetemporomandibular joint. Br J Oral Maxillofac Surg 1988;26:297–305.

7. Trias A, Quintana O. Synovial chondrometaplasia: review of worldliterature and a study of 18 Canadian cases. Can J Surg 1976;19:151–158.

8. Jaffe HL. Tumors and tumorous conditions of the bones and joints.Philadelphia: Lea & Febiger; 1985. p 558–566.

GUPTA ET AL.

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