Extra-articular synovial chondromatosis is a rare entity in the foot and ankle. We present a case of a 49-year-old female who presented for evaluation of a palpable concern following trauma; which was found to represent synovial chondromatosis. This case demonstrates the multimodality imaging findings, including ultrasound and MRI, with histopathologic correlation

Abraham, John

Dheer, Sachin

Jiang, Wei

Karanjia, Homyar

Schick, Faith

Sullivan, Paul E

Taweel, Nicholas

English

Jefferson Digital Commons

Thomas Jefferson University Jefferson Digital Commons Department of Radiology Faculty Papers Department of Radiology 2-21-2020 Extra-articular synovial chondromatosis of the ankle: Unusual case with radiologic-pathologic correlation. Sachin Dheer Thomas Jefferson University Hospital Paul E Sullivan Rothham institute Faith Schick Rothman Institute Homyar Karanjia Rothman Institute Nicholas Taweel Rothman Institute See next page for additional authors Follow this and additional works at: https://jdc.jefferson.edu/radiologyfp  Part of the Radiology Commons Let us know how access to this document benefits you Recommended Citation Dheer, Sachin; Sullivan, Paul E; Schick, Faith; Karanjia, Homyar; Taweel, Nicholas; Abraham, John; and Jiang, Wei, "Extra-articular synovial chondromatosis of the ankle: Unusual case with radiologic-pathologic correlation." (2020). Department of Radiology Faculty Papers. Paper 81. https://jdc.jefferson.edu/radiologyfp/81 This Article is brought to you for free and open access by the Jefferson Digital Commons. The Jefferson Digital Commons is a service of Thomas Jefferson University's Center for Teaching and Learning (CTL). The Commons is a showcase for Jefferson books and journals, peer-reviewed scholarly publications, unique historical collections from the University archives, and teaching tools. The Jefferson Digital Commons allows researchers and interested readers anywhere in the world to learn about and keep up to date with Jefferson scholarship. This article has been accepted for inclusion in Department of Radiology Faculty Papers by an authorized administrator of the Jefferson Digital Commons. For more information, please contact: JeffersonDigitalCommons@jefferson.edu. Authors Sachin Dheer, Paul E Sullivan, Faith Schick, Homyar Karanjia, Nicholas Taweel, John Abraham, and Wei Jiang This article is available at Jefferson Digital Commons: https://jdc.jefferson.edu/radiologyfp/81 R a d i o l o g y  Ca s e  R e p o r t s  1 5  ( 2 0 2 0 )  4 4 5 – 4 4 9  Available online at www.sciencedirect.com journal homepage: www.elsevier.com/locate/radcr Case Report Extra-articular synovial chondromatosis of the ankle: Unusual case with radiologic-pathologic correlation Sachin Dheer, MD a , ∗, Paul E. Sullivan, DPM b , Faith Schick, DPM b , Homyar Karanjia, DPM c , Nicholas Taweel, DPM b , John Abraham, MD d , Wei Jiang, MD, PhD e a Department of Radiology, Jefferson Health, 111 South 10th Street, Philadelphia, PA 19103, USA b Rothman Institute, Department of Podiatry, Philadelphia, PA, USA c Rothman Institute, Director, Department of Podiatry, Philadelphia, PA, USA d Rothman Institute, Department of Orthopaedics, Philadelphia, PA, USA e Department of Pathology, Thomas Jefferson University Hospital, Philadelphia, PA, USA a r t i c l e i n f o Article history: Received 24 December 2019 Revised 22 January 2020 Accepted 25 January 2020 Keywords: Synovial chondromatosis Extra-articular Ankle MRI Ultrasound Pathology a b s t r a c t Extra-articular synovial chondromatosis is a rare entity in the foot and ankle. We present a case of a 49-year-old female who presented for evaluation of a palpable concern following trauma; which was found to represent synovial chondromatosis. This case demonstrates the multimodality imaging findings, including ultrasound and MRI, with histopathologic correlation. © 2020 The Authors. Published by Elsevier Inc. on behalf of University of Washington. This is an open access article under the CC BY-NC-ND license. ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ) Introduction Extra-articular synovial chondromatosis (SC) is a rare, benign mass that arises from synovium found in joints and tendon sheaths. This condition is most commonly observed in the knee joint (50%), but any synovium containing site can be affected. Although benign, the abnormal synovium in this Competing Interests: None. ∗ Corresponding author. E-mail address: sachdheer@yahoo.com (S. Dheer). condition can calcify, and generate loose bodies within the joint. Both the gritty calcified synovial surface and the loose bodies can damage cartilage, causing a secondary osteoarthri- tis. In severe instances, the loose bodies can occupy the entire joint and penetrate into adjacent tissues. It is not clear if SC is a neoplastic or metaplastic condition, since a specific genetic abnormality has not yet been identified. SC occurs in men twice as often as women, and most commonly in patients https://doi.org/10.1016/j.radcr.2020.01.031 1930-0433/© 2020 The Authors. Published by Elsevier Inc. on behalf of University of Washington. This is an open access article under the CC BY-NC-ND license. ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ) 446 R a d i o l o g y  Ca s e  R e p o r t s  1 5  ( 2 0 2 0 )  4 4 5 – 4 4 9  30-50 years of age. Primary SC is known as Reichel syndrome, whereas secondary SC is the result of degenerative changes from other intra-articular conditions. Malignant degeneration to chondrosarcoma has been reported, however is rare [1–3] . Case report A 49-year-old female sustained a traumatic ankle injury as the result of a twist and fall. She was seen at an urgent care im- mediately following the injury where initial x-rays were taken, and negative for fracture. A noncontrast MRI was ordered. The patient then presented to our office for further care. She had no history of prior ankle abnormality. A palpable mass was noted at the lateral ankle on clinical exam which patient stated appeared following the injury. The MRI findings showed a large multinodular, presumably cystic, lesion mea- suring approximately 5.0 × 2.2 × 3.8 cm in the inferolateral ankle and was reported as probable large ganglion ( Fig. 1 A, B, C). The patient was referred for an ultrasound-guided aspiration which revealed a 5.0 × 5.0 × 5.0 × 3.0 cm lobulated highly heterogeneous and vascular soft tissue mass with both arterial and venous waveforms; which was reported as suggestive of a neurogenic tumor or sarcoma ( Fig. 2 A, B, C). A follow-up MRI with intravenous contrast ( Fig. 1 D, E) re- vealed a lobulated mass located in close proximity to the tendon sheath of the peroneal tendons, with a peripheral and mildly nodular and lace-like internal enhancement pattern. Proposed diagnoses included a myxoid neoplasm or a syn- ovial sarcoma based on location in the foot. The mass was measured at 6.0 × 4.0 × 3.0 cm ( Fig. 2 ). The decision was made to perform an intraoperative ultrasound guided biopsy of the lesion. Surgical pathology suggested a benign cartilaginous Fig. 1 – MRI of the ankle. (A) Axial (long-axis) T1-weighted image demonstrates a large, lobulated soft tissue lesion at the lateral aspect of the ankle, of intermediate signal intensity, deforming the skin surface. The externally placed vitamin marker (arrow) demarcates the area of palpable concern. (B) Coronal (short-axis) proton density, fat saturated image further demonstrates the lobulated, septated nature of the lesion, and confirms the intimate relationship with the underlying peroneal tendons. (C) Sagittal, T2-weighted, fat saturated image, demonstrating the increased, fluid-like signal within the lesion, consistent with a high fluid content, and also demonstrates the normal, adjacent peroneal tendons. Following the intravenous administration of gadolinium-based contrast, (D) axial (long-axis) and (E) sagittal T1-weighted, fat saturated images demonstrate a peripheral and internal, “lace-like” pattern of enhancement, suggestive of a chronic, inflammatory process as opposed to neoplasm. R a d i o l o g y  Ca s e  R e p o r t s  1 5  ( 2 0 2 0 )  4 4 5 – 4 4 9  447 Fig. 2 – Ultrasound of the lateral ankle. (A) Grey-scale image demonstrates the lobulated contour of the lesion, with heterogeneous, internal echogenicity, not consistent with a simple ganglion or tenosynovitis. Doppler interrogation of the mass demonstrates (B) arterial and (C) venous blood flow; together indicating neovascularity, due to an inflammatory and/or neoplastic process. lesion, consistent with SC and complete surgical excision of the mass was advised and subsequently performed, in the same setting. During surgery, the mass was noted superior to and arising from the tendon sheath. Histologic evaluation noted well-circumscribed lobular fragments of cartilaginous proliferation with low cellularity and low nuclear-to-cytoplasmic ratios. There was no nuclear atypia, mitoses, or necrosis. The findings were compatible with a benign cartilaginous proliferation, most consistent with SC ( Fig. 3 ). At her initial 2-week postoperative visit, the patient had full range of motion, normal strength, and normal neurovas- cular status. At 4 and 10-month follow ups, the patient had no complaints or limitations. Discussion Extra-articular SC is rare in the foot and ankle and patho- genesis remains unclear. It is usually monoarticular and the 448 R a d i o l o g y  Ca s e  R e p o r t s  1 5  ( 2 0 2 0 )  4 4 5 – 4 4 9  Fig. 3 – Histologic findings of the ankle lesion (A and B). Well circumscribed lobular fragments of cartilaginous proliferation (C and D). The cellularity is low, with no nuclear atypia, mitosis, or necrosis.(A. at 10 ×; B. at 20 ×; C. at 100 ×; D. at 200 ×.) occurrence rate is approximately 1 per 100,000 [3] . Literature review reveals 7 reported cases in the foot and ankle, with locations including the tibiotalar, calcaneocuboid, navicu- locuneiform, tarsometatarsal, metatarsophalangeal, and interphalangeal joints [4] . Most cases of extra-articular SC indicate patients have symptoms for several years before di- agnosis and surgical intervention. Symptoms usually include pain, locking, instability, and palpable mass [1] . This patient was not symptomatic: however, the findings were discovered incidentally as a result of a traumatic injury which led to early diagnosis and treatment. The disease can be classified into 3 phases based on mat- uration. Milgram described this classification system in 1977: early, transitional, and late. Early phase is described as active synovial disease without the presence of loose bodies. Tran- sitional phase is described as the presence of synovial dis- ease and loose bodies. Late phases is described as loose bodies without synovial involvement [5] . The MRI appearance of SC has been reported as variable, including loose bodies, which were absent in our case, prolifer- ative synovium and pressure erosions. The use of intravenous contrast is helpful in distinguishing synovial fluid from highly vascular synovial tissue. The enhancement pattern in our case primarly suggested synovial fluid with a lining of synvovial tissue. MRI often also shows areas of signal void on all pulse sequences that correspond to calcification [6–8] , which was notably absent in our case. SC on MRI can be mistaken for pigmented villonodular synovitis since both appear with sig- nal voids, however, the synovial lining in pigmented villon- odular synovitis will typically show low MRI signal because of hemosiderin deposits [6 ,9] . CT imaging can be useful in de- tecting calcified loose bodies that are a result of primary SC and distinguish from more localized loose bodies that are sec- ondary to degenerative osteoarthritis (OA). Histologic analysis via biopsy and/or surgical frozen sec- tion is helpful in determining the surgical procedure before total excision. SC has some histologic features that are also found in low-grade chondrosarcoma including binucleated chondrocytes, although this does not imply malignancy. Five features have been described in successfully differentiating SC from chondrosarcoma. These include (1) chondrocytes arranged in sheets in SC (rather than clusters in cases of chondrosarcoma), (2) myxoid change in SC (vs enhancing, solid matrix in chondrosarcoma), (3) the absence of hyper- cellularity and crowding and/or spindling of nuclei at the periphery in SC, but present in chondrosarcoma, (4) the absence of necrosis in SC, which is seen in chondrosarcoma, and finally (5) SC involvement of adjacent bone margins is R a d i o l o g y  Ca s e  R e p o r t s  1 5  ( 2 0 2 0 )  4 4 5 – 4 4 9  449 described as “pushing” (aka—without infiltrative features), whereas chondrosarcoma demonstrates permeation and/or infiltration of trabecular bone [4 ,10 ,11] . It has been reported that the relative risk of malignant transformation in SC can be as high as 5%. It is not known whether intra-articular and extra-articular variants carry the same risk of malignant degeneration. Recurrence has been re- ported to range from 37.5% to over 50%; although these re- ported rates can be biased due to incomplete resection or mis- diagnosis [2 ,12] . This patient’s early diagnosis and treatment has allowed for a quick return to normal active lifestyle with- out evidence of malignancy or recurrence. Curative treatment of extra-articular SC is typically per- formed with en bloc, complete surgical excision. Recurrence, which is attributed to incomplete excision, is extremely low. In keeping with the benign histology, there is currently no role for either preoperative or postoperative, adjuvant radiation or chemotherapy. If, following surgical pathologic evaluation, malignant features are found, treatment includes wider sur- gical resection (if needed) and adjuvant chemotherapy and/or radiation, depending on institutional protocols [2–4 ,10] . R E F E R E N C E S  [1] Dorfman HD , Czerniak B . Synovial lesions. Bone tumors. St Louis, Mo: Mosby; 1998. p. 1041–86 .[2] Bertoni F , Unni KK , Beabout JW , Sim FH . Chondrosarcomas of the synovium. Cancer 1991;67:155–62 .[3] Villacin AB , Brigham LN , Bullough PG . Primary and secondary synovial chondrometaplasia: histopathologic and clinicoradiologic differences. Hum Pathol 1979;10:439–51 .[4] Galat D , Ackerman D , Spoon D , Turner N , Shives T . Synovial chondromatosis of the Foot and Ankle. Foot Ankle Int 2008;29(3):312–17 .[5] Milgram JW . Synovial osteochondromatosis: a histopathological study of thirty cases. J Bone Joint Surg Am 1977;59:792–801 .[6] Harish S , Saifuddin A , Cannon S , Flanagan A . Synovial chondromatosis of the foot presenting with Lisfranc dislocation. Skeletal Radiol 2005;34:736–9 .[7] Kramer J , Recht M , Deely DM , Schweitzer M , Pathria MN ,Gentili A , et al. MR appearance of idiopathic synovial osteochondromatosis. J Comput Assist Tomogr 1993;17:772–6 .[8] Narvaes JA , Narvaez J , Aguilera C , DeLama E , Portabella F . MR imaging of synovial tumors and tumor-like lesions. Eur Radiol 2001:2549–60 .[9] Hughes TH , Sartoris DJ , Schweitzer ME , Resnick DL . Pigmented villonodular synovitis: MRI characteristics. Skeletal Radiol 1995;24:7–12 .[10] Davis RJ , Hamilton A , Biggart JD . Primary synovial chrondromatosis: a clinicopathological review and assessment of malignant potential. Hum Pathol 1998;29:683–8 .[11] Hermann G , Klein M , Abdelwahab I . Synovial Chondrosarcoma arising in synovial chondromatosis of the right hip. Skeletal Radiol 1997;26:366–9 .[12] Davis RI , Hamilton A , Biggart JD . Primary synovial chondromatosis: a clinicopathologic review and assessment of malignant potential. Hum Pathol 1998;29:683–8 .

Extra-articular synovial chondromatosis of the ankle: Unusual case with radiologic-pathologic correlation.

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Extra-articular synovial chondromatosis of the ankle: Unusual case with radiologic-pathologic correlation.

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