Treating Clear Cell Hidradenoma Of The Dorsal Medial Forefoot
These authors detail the diagnosis and treatment of a 76-year-old patient who presented with a painless palpable mass along her dorsal first metatarsal shaft, a mass that had increased in size over the past few years.
Clear cell hidradenomas are relatively rare dermal sweat gland neoplasms believed to originate from the eccrine glands. These neoplasms are composed of two main cell types: a fusiform dense cell epidermoid and small amounts of glycogen, and a large “clear” cell, filled with glycogen.1 The neoplasm has both solid and cystic components, and cell types include epidermoid cells, which may transform into clear cells.1-3
Clear cell hidradenomas typically present as a solitary non-encapsulated dermal nodule, vary in coloration and have the potential for extension into the subcutaneous fat.1-3 Slightly more common in women with a ratio of 1.7 to 1, they most commonly occur on the head, upper limb and trunk, and mostly occur in middle age.1-4
A 76-year-old female with a past medical history of high cholesterol, pheochromocytoma and multiple lipoma and schwannoma resections presented over the course of three years for a painless palpable mass along her dorsal first metatarsal shaft. The patient stated the mass had been present since 2003. Upon initial presentation to the Foot and Ankle Institute at the Temple University School of Podiatric Medicine in 2008, the patient had a palpable, firm, superficial, nodular mass approximately 1.5 cm x 2.0 cm. The mass was non-fluctuant and reddish in color.
The patient stated that the mass had slowly increased in size over the past few years but was not painful. She denied any traumatic event to the area. The results of magnetic resonance imaging (MRI) favored a hemangioma or vascular malformation. Over the next two years, the patient refused excision of the mass. However, during this time, she had multiple soft tissue masses excised from different body regions. The soft tissue masses included a schwannoma from her posterior left calf. In 2011, the patient presented to the clinic. At this time, she stated that the previously painless mass was not only growing in size and changing in color, but was now causing her pain and discomfort in shoe gear and with ambulation. We obtained a second MRI prior to surgical excision.
The lower extremity physical examination showed palpable dorsalis pedis and posterior tibial pulses bilaterally, and normal capillary refill time. Sensation was normal to light touch, and there were 2/4 patellar and Achilles tendon reflexes. The patient had full muscle strength to all quadrants bilaterally. Abduction and valgus rotation of the hallux were present bilaterally but more severe on the left. She had decreased range of motion at the first metatarsophalangeal joints (MPJ) bilaterally but no pain with motion. Just medially and proximally to the left first MPJ, there was a palpable, superficial, non-fluctuant mass, which was immovable and purple. The mass measured 2.5 cm x 3.0 cm at that time.
A Closer Look At The MRI Results
The MRI examination obtained in 2008 of the left forefoot and midfoot occurred via a 1.5-Tesla scanner using a combination of axial and coronal T1 weighted spin-echo and axial, sagittal and coronal fat saturated T2-weighted spin-echo imaging sequences. In addition, physicians obtained fat saturated pre- and post-contract early and delayed axial images following uneventful administration of 13 cc of intravenous gadolinium. Physicians marked the site of the clinically palpable abnormality with a vitamin E capsule.