Chondroid syringoma (Mixed tumor of the skin)

Are You Confident of the Diagnosis?

Chondroid syringoma, or cutaneous mixed tumor, is an adnexal neoplasm of either apocrine or eccrine origin. It presents as a firm, dermal or subcutaneous nodule, usually between 0.5 and 3 cm. While usually solitary, cases with multiple lesions have been reported. As there is no distinctive clinical appearance, it is often misdiagnosed as another entity, such as epidermoid cyst, pilar cyst, or neurofibroma, prior to biopsy.

What you should be alert for in the history

Most patients with chondroid syringoma are in the age range of 20 to 60 years, although it has also been seen in children. The history will usually be one of a slow-growing, painless nodule. Rapid growth or ulceration should prompt concern for a malignant chondroid syringoma, although these are very rare.The malignant variant is more likely to occur on the trunk and extremities, and is more common in females.

Characteristic findings on physical examination

A chondroid syringoma is most commonly found on the head, neck, and scalp (Figure 1). Less frequently, it may also be seen on the trunk, axilla, inguinal area, and genitalia; rarely, it has been reported on the eyelid and external auditory canal. Lesions on the head and neck have a male predilection, but there is an equal sex distribution for other sites.

Figure 1.

Chondroid syringoma on the vertex of the scalp.

Expected results of diagnostic studies

Histologic examination is the definitive method to confirm the diagnosis. A well-circumscribed nodule is seen within the deep dermis or subcutis. The tumors are called “mixed” because of the biphasic pattern of epithelial structures within a mesenchymal stroma. The stroma is abundant, and can be chondroid, myxoid, fibrous, or even osseous.

The epithelial component is predominantly either apocrine or eccrine, although folliculosebaceous elements can also be seen. The apocrine type has tubular and cystic branching lumina lined by a double row of epithelial cells and demonstrating decapitation secretion. The eccrine type has ducts with smaller lumens lined by a single row of epithelial cells. The presence of cellular atypia, mitotic figures, necrosis, or an infiltrative pattern are concerning for malignancy.

The histologic appearance is similar to that of mixed tumor of the salivary gland (pleomorphic adenoma), however the latter has a much higher incidence of local recurrence and greater potential for malignant transformation.

Who is at Risk for Developing this Disease?

Most patients with chondroid syringoma are in the age range of 20 to 60 years, although it has also been seen in children.

What is the Cause of the Disease?

Although their exact origin is still unclear, chondroid syringomas have traditionally been classified into apocrine and eccrine types, based on the epithelial component of the lesion. More recently, it has been proposed that these lesions be classified as hamartomas rather than adnexal adenomas.

Systemic Implications and Complications

Chondroid syringoma is a benign growth, with little proliferative capacity. After removal, the risk of recurrence is very low. There is no systemic involvement and no associated conditions or disease states.

Most cases of malignant chondroid syringoma originate de novo, but rarely an exisiting benign mixed tumor may suddenly undergo malignant changes. The aggressive behavior of these may vary widely from local recurrence only to regional lymph node spread to bone or visceral metastases.

Treatment Options

Treatment options are sumarized in Table I.

Table I.
Surgical procedures
CO2 laser

Optimal Therapeutic Approach for this Disease

Simple excision is the treatment of choice for chondroid syringoma. They are usually well-circumscribed, encapsulated, white nodules, so dissection from surrounding tissue is usually uncomplicated. Risk of recurrence is minimal, and large margins of excision are not necessary.

Other treatment options that have been used include electrodessication and CO2 laser. However, the risk of recurrence with these procedures may be slightly higher.

With their higher recurrence rate and metastatic potential, a complete surgical excision should be performed for malignant chondroid syringoma, with histologic examination of all edges to insure that no tumor remains. There are, however, no standard recommended margins for removal of these lesions.

Patient Management

No follow-up is necessary for most cases of chondroid syringoma. If the lesion is excised, it will usually not recur. For cases that have been biopsied but not excised, the patient may elect for observation instead of surgical treament. In these instances, a return visit is only necessary if any changes are noticed in the lesion.

For the rare cases of malignant chondroid syringoma, periodic follow-up is warranted after the lesion has been completely excised. The patients should be monitored for any recurrence as well as for lymphadenopathy.

Unusual Clinical Scenarios to Consider in Patient Management

The diagnosis of chondroid syringoma is not usually made clinically, and thus biopsy or excision is usually performed.

In cases of larger or deeper lesions, magnetc resonance imaging (MRI0 may be of value. Whereas there are no specific MRI features of chondroid syringoma, it can be a useful study to determine the extent and depth of the lesion as well as relation to adjacent anatomic structures.

What is the Evidence?

Yavuzer , R, Basterzi , Y, Sari , A, Bir , F, Sezer , C. “Chondroid syringoma: a diagnosis more frequent than expected”. Dermatol Surg . vol. 29. 2003. pp. 179-81. (A retrospective analysis of surgeries performed for other diagnoses in which chondroid syringoma was detemined to be the actual diagnosis after postoperative histologic examination.)

Agrawal , A, Kumar , A, Sinha , A, Kumar , B, Sabira , K. “Chondroid syringoma”. Singapore Med J . vol. 49. 2008. pp. 33-4. (A case report and review of the literature.)

Kaushik , V, Bhalla , R, Nicholson , C, Carpentier , J. “The chondroid syringoma: report of a case arising from the external auditory canal”. Eur Arch Otorhinolaryngol . vol. 262. 2005. pp. 868-70. (A case report describing an unusual location for syringoma presentation.)

(Laxmisha , C, Thappa , D, Jayanthi , S. “Chondroid syringoma of the earlobe”. J Eur Acad Dermatol Venereol . vol. 21. 2007. pp. 276-7. (A case report describing an unusual location for syringoma presentation.)

Turhan-Haktanir , N, Sahin , O, Bukulmez , A, Demir , Y. “Chondroid syringoma in a child”. Pediatr Dermatol . vol. 24. 2007. pp. 505-7. (A pediatric case report.)

Awasthi , R, Harmse , D, Courtney , D, Lyons , C. “Benign mixed tumor of the skin with extensive ossification and marrow formation”. J Clin Pathol. vol. 57. 2004. pp. 1329-30. (A case report describing a syringoma with unusual histologic features.)

Hafezi-Bakhtiara , S, Al-Habeeb , A, Ghazarian , D. “Benign mixed tumor of the skin, hypercellular variant”. J Cutan Pathol. vol. 37. 2010. pp. 46-9. (A case report and review of the literature.)

Mandeville , J, Roh , J, Woog , J, Gonnering , R, Levin , P. “Cutaneous benign mixed tumor of the eyelid: clinical presentation and management”. Ophthal Plas Recon Surg. vol. 20. 2004. pp. 110-6. (A review of diagnosis and treatment.)

Kerimoglu , U, Aydingoz , U, Ozkaya , O, Aksu , A, Ergen , F. “MRI of a benign chondroid syringoma”. Brit J Radiol . vol. 79. 2006. pp. 59-61. (A description of MRI findings and review of potential uses for this imaging modality.)

Nicolaou , S, Dubec , J, Munk , P, O’Connell , J, Lee , M. “Malignant chondroid syringoma of the skin: magnetic resonance imaging features”. Austral Radiol . vol. 45. 2001. pp. 240-3. (A description of MRI findings and indications for imaging these lesions.)