Page 1 of 5 © AME Medical Journal. All rights reserved. AME Med J 2020;5:33 | http://dx.doi.org/10.21037/amj-20-24 Introduction Clear cell hidradenoma is a sweat gland neoplasm of eccrine or apocrine differentiation. It has a slow and self-limited growth pattern. While it may occur in any age group, it is more commonly observed in the middle-aged and elderly (1). Clear cell hidradenoma may occur in any part of the body. To the best of our knowledge, this report is the frst case of a clear cell hidradenoma arising from the plantar aspect of the foot. We present the following article in accordance with the CARE reporting checklist. Case presentation A 66-year-old male presented to the orthopedic clinic with a slow growing soft tissue lump near the right heel for 2 years. The lesion was partially excised 1 year back, including the removal of a foreign body, possibly glass. The slow growing mass was associated with mild intermittent pain. The skin overlying the mass was elevated but there was no evidence of ulceration or discoloration. Sonography of the plantar aspect of the right lateral heel demonstrated a 1.5 × 1.0 × 0.5 cm 3 heterogeneous soft tissue mass with a thick echogenic wall and central hypoechoic area. There was no appreciable color flow on Doppler imaging (Figure 1). Sonographic findings were non-specific and differentials included chronic foreign body granuloma in view of possible glass excision. The patient underwent a biopsy, which revealed clear cell hidradenoma. Subsequently, the lesion grew in size and became increasingly painful. MRI was performed to assess the margins and depth of the lesion. The lesion was hyperintense on T2 weighted images and demonstrated intermediate signal on T1 weighted image (Figure 2). Based on these findings, it was determined that he should have surgical intervention with wide excision. Histopathology showed a dome-shaped lesion comprised of spindled and stellate cells with atypical, hyperchromatic nuclei and focally prominent nucleoli. Multinucleated giant cells were also present (Figure 3). Clinical follow up after 6 months has shown no recurrence (Figure 4). Case Report Clear cell hidradenoma of the foot: a case report with literature review Darshan Gandhi 1 , Kriti Ahuja 2 , Pankaj Nepal 1 , Harpreet Sawhney 3 , Pranav Sharma 3 , Ruben Kier 1 1 Department of Diagnostic Radiology, St. Vincent’s Medical Center at Hartford Healthcare, Bridgeport, CT, USA; 2 MBBS, Maulana Azad Medical College, New Delhi, Delhi, India; 3 Department of Diagnostic Radiology, Bridgeport Hospital at Yale New Haven Health, Bridgeport, CT, USA Correspondence to: Kriti Ahuja. Maulana Azad Medical College, 2, Bahadur Shah Zafar Marg, New Delhi, Delhi 110002, India. Email: kriti5ahuja@gmail.com. Abstract: We present an interesting case of clear cell hidradenoma of the foot masquerading as foreign body granuloma for 2 years in a patient presenting with a slow growing soft tissue lump near the right heel. Biopsy revealed the diagnosis and the patient was successfully managed surgically with no recurrence six months later. This is one of the frst acknowledged cases of benign, clear cell hidradenoma of the foot. We have elaborated the imaging features correlating with morphological, histological findings and close differentials to be considered by physicians, in this case report to guide the management of patients with a complex superfcial subcutaneous mass. It is important to consider hidradenoma as a differential diagnosis in case of a slow growing complex superfcial mass in any location and manage such cases with wide surgical excision to prevent recurrence. Keywords: Case report; foot tumor; hidradenoma; imaging; MRI; sweat gland Received: 19 February, 2020. Accepted: 11 May, 2020; Published: 25 September 2020. doi: 10.21037/amj-20-24 View this article at: http://dx.doi.org/10.21037/amj-20-24