Indian Journal of Pathology and Microbiology
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Year : 2012  |  Volume : 55  |  Issue : 2  |  Page : 259-260
Extraskeletal osteochondroma of the arm masquerading as chondroid syringoma: A diagnostic pitfall on cytology

Department of Pathology, Maulana Azad Medical College and Associated Lok Nayak Hospital, New Delhi, India

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Date of Web Publication3-Jul-2012

How to cite this article:
Singh N, Khurana N, Jain S. Extraskeletal osteochondroma of the arm masquerading as chondroid syringoma: A diagnostic pitfall on cytology. Indian J Pathol Microbiol 2012;55:259-60

How to cite this URL:
Singh N, Khurana N, Jain S. Extraskeletal osteochondroma of the arm masquerading as chondroid syringoma: A diagnostic pitfall on cytology. Indian J Pathol Microbiol [serial online] 2012 [cited 2022 Jul 1];55:259-60. Available from: https://www.ijpmonline.org/text.asp?2012/55/2/259/97901


Osteochondromas (OC) are benign bony lesions, which may rarely be found in the soft tissues without any osseous or articular involvement and are designated as extraskeletal osteochondromas (ESOC). [1],[2] We report a case of a solitary ESOC in a young male in whom a fine needle aspiration cytology (FNAC) possibility of chondroid syringoma (CS) was suggested in view of abundant cartilaginous material. The case is presented here for its diagnostic pitfall on cytology.

A 30-year-old man presented with a slowly progressive painless swelling in the left arm for the past 4 months. The mass was subcutaneous, firm, freely mobile, nontender, and the overlying skin was unremarkable. The patient was referred for FNAC. Giemsa-stained smears showed abundant, dense clumps of metachromatically stained chondroid stroma and fair number of entrapped bland looking cells. These cells were medium to large sized with moderate amount of vacuolated pale cytoplasm; there was no atypia, mitoses, or pleomorphism [Figure 1]. Thus, the diagnosis of a benign adnexal skin tumor with a possibility of CS was suggested. The mass was surgically excised and measured 2 × 1.5 × 1 cm. The cut surface was lobulated, gray-white with focal bony hard areas. The periphery of the swelling revealed a glistening thin white cap. Histological sections revealed well-formed bony cortex and medulla, surrounded by a mature hyaline cartilaginous cap [Figure 2]. Hence, the final histological diagnosis was ESOC.
Figure 1: FNAC smears: (a) shows benign looking cells in abundant magenta stained chondroid material; and (b) shows many benign chondrocytes with foamy cytoplasm lying in chondroid material. a: (Giemsa stain, ×250) b: (Giemsa stain, ×300)

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Figure 2: Histopathology of the resected mass: Shows bony cortex and medulla with cartilaginous cap. (Hematoxylin and eosin, ×250)

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ESOC are rare lesions, reported in hands, feet, neck, thigh, buttock, and rarely in the oral cavity. [1],[2],[3] They present as well-delineated soft-tissue masses not attached to the adjacent bone. Radiological investigations like X-ray and computerized tomography (CT) scan demonstrate the extra skeletal site and are sufficient to confirm the diagnosis. In the present case, radiological investigations were not carried out because the patient presented with a soft-tissue mass which was clinically unsuspected of this rare entity.

Most of the OC undergo surgical excision based on radiology alone and are not subjected to FNAC. Hence, the cytological literature on OC as such is very scanty, leave alone ESOC. Moreover, FNAC is considered inappropriate in the diagnosis of cartilaginous tumors. The needle may sample only the superficial cartilaginous cap and the dense cartilaginous material does not smear well. [4]

In the present case, FNAC was performed in a case clinically unsuspected of ESOC. The smears showed abundant magenta stained chondroid fragments with entrapped bland chondrocytes, and thus, was misdiagnosed as cartilaginous benign skin adnexal tumor on cytology. The cytologic features showed an overlap with CS, which is a rare benign skin adnexal tumor. CS presents as a slow growing subcutaneous mass in the head and neck region and rarely in the arm. [5] Thus, there is a considerable clinical and cytologic overlap between ESOC and CS. This morphologic pitfall was further compounded by the rare nature of this lesion and lack of published cytological literature.

To conclude, the present case highlights the cytological features of ESOC and its cytologic mimic with CS. Cytologists should consider the possibility of ESOC in presence of abundant chondroid material in smears from a solitary, hard, ossified soft-tissues mass lesion especially from extremities. A clinicoradiological and histopathological correlation is mandatory for a definite diagnosis.

   References Top

1.Siong Kho VK, Chen WC. Extraskeletal osteochondroma of the foot. J Chin Med Assoc 2010;73:52-5.  Back to cited text no. 1
2.Singh R, Sharma AK, Magu NK, Kaur KP, Sen S, Magu S. Extraskeletal osteochondroma in the nape of the neck: A case report. J Orthop Surg 2006;14:192-5.  Back to cited text no. 2
3.Gulati Y, Maheshwari A, Sharma V, Mattoo R, Arora D, Gupta N. Extra skeletal osteochondroma of the thigh: A case report. Acta Orthop Belg 2005;71:115-8.  Back to cited text no. 3
4.Ackerman M. Bone. In: Orell SR, Sterrett GF, Whitaker D, editors. Fine needle aspiration cytology. 4 th ed. UK: Elsevier; 2005. p. 125-38.   Back to cited text no. 4
5.Kumar B. Chondroid syringoma diagnosed by fine needle aspiration cytology. Diagn Cytopathol 2010;38:38-40.  Back to cited text no. 5

Correspondence Address:
Shyama Jain
20/59, Lodhi Colony, New Delhi - 110 003
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0377-4929.97901

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