May 2018 Case of the Month - Further Information

Submitted by Dr Yamini Krishna & Natalie Meara

Clinical History:  

A 69 year old female presented to her GP with an 8 month history of an asymptomatic but progressively enlarging nodular lesion on the scalp.  Her past medical history included: type 2 diabetes mellitus, hypertension, chronic obstructive pulmonary disease and was an ex-smoker.  On examination, there was a non-tender, non-ulcerated, firm, mobile oval lump 5mm diameter on the scalp.  The lesion was excised and sent for histopathology.

 

Macroscopic Description:  

The specimen comprised an ellipse of skin measuring 13x6mm with up to 6mm of underlying tissue.  There was an opening on the surface measuring 3mm in diameter, connecting to an underlying nodule measuring 6mm in diameter.

 

Microscopic Description:  

Sections revealed skin containing a well-circumscribed dermal lesion.  The lesion comprised abundant myxochondroid stroma with prominent small ductal structures lined by a single layer of simple cuboidal epithelium.  The appearances were that of a dermal chondroid syringoma or benign mixed stromal There was no evidence of necrosis, nuclear atypia or malignancy.  The lesion had been incompletely excised and was present at the peripheral and deep margins.

 

Diagnosis:  

Dermal chondroid syringoma

 

Discussion: 

Chrondroid syringoma is a rare, benign skin tumour arising from the sweat glands with an incidence of approximately 0.01 to 0.098% of all primary skin tumours.  It is also known as a cutaneous pleomorphic adenoma, benign mixed cutaneous tumour or eccrine mixed tumour as it contains both epithelial and mesenchymal elements. It was first described as a mixed tumour of the skin with histological resemblance to a salivary pleomorphic adenoma by Billroth in 1859.  In 1961, Hirsch and Helwig coined the term ‘chondroid syringoma’ due to presence of sweat glands in a chondroid stroma.1-3   The aetiology and risk factors for their development is still unknown.  The lesions are usually solitary, present in the middle-aged to elderly and typically occur on the head and neck with a male preponderance, but have been reported to occur rarely in other regions such as: extremities, trunk, axilla, groin, eyelid and auditory canal.  Due to their rarity, they are often clinically misdiagnosed as other benign tumours of epidermal or mesenchymal appendages, such as dermoid, epidermal cyst, pilar cyst, sebaceous cyst, pilomatrixoma, trichoepithelioma, basal cell carcinoma or neurofibroma.  Diagnosis is only confirmed on histology.3-6

Chrondroid syringomas are typically well-circumscribed small dermal lesions (typically <1cm), though they may extend into the subcutis, with no epidermal attachment.  They comprise an admixture of epithelial-myoepithelial structures arranged in cords or forming tubules/ducts within a chondromyxoid and fibrous stroma.  The tubules/ducts are lined by a single or bilayer of epithelial cells (outer myoepithelial cells), which are cytokeratin+, EMA+, CEA+ and/or vimentin+, S-100 protein or neuron-specific enolase (NSE) respectively.  Nests of polygonal cells or keratin cysts may also be seen.  Importantly there is no necrosis or cellular atypia. 3-5  Necrosis, nuclear pleomorphism with mitoses and infiltrative growth pattern would indicate a malignant chondroid syringoma, which is extremely rare but has been reported on the truck and extremities in young females.1, 3  

The treatment of choice is complete surgical excision and is curative.  Narrow clear surgical margins are acceptable, although there is no published recommendation.  The patient can be safely discharged if excision is complete as recurrence is exceptionally rare.  However, follow up is required if excision is incomplete and/or there is any atypia due to risk, though extremely rare, of malignant transformation and metastases.1,3,4,6

Practice Points: 

  • Chondroid syringoma is a rare, benign skin adnexal tumour which predominantly occurs in the head and neck region.
  • They often misdiagnosed due their rarity and unremarkable clinical presentation.
  • Chondroid syringoma should enter the differential diagnosis of any small cutaneous nodule in the head or neck area of middle-aged patients.
  • Treatment of choice is complete surgical excision to confirm diagnosis and prevent risk of recurrence or malignancy.

References

  1. 1. Tural D, Selçukbiricik F, Günver F, Karışmaz A, Serdengecti S. Facial Localization of Malignant Chondroid Syringoma: A Rare Case Report. Case Reports in Oncological Medicine 2013; Article ID 907980: 1-3. doi:10.1155/2013/907980.
  1. 2. Hirsch P, Helwig EB. Chondroid syringoma Mixed tumour of skin, salivary gland type. Arch Dermatol1961; 84: 835–47.
  1. 3. Agrawal A, Kumar A, Sinha A K, Kumar B, Sabira K C. Chondroid syringoma. Singapore Med J 2008; 49: 33-4.
  1. 4. Sivamani R, Wadhera A, Craig E. Chondroid syringoma: Case report and review of the literature. Dermatology Online Journal 2006; 12:8. (https://escholarship.org/uc/item/2kg558r6)
  1. 5. Nasit JG, Dhruva G. Chondroid Syringoma: A Diagnosis by Fine Needle Aspiration Cytology. J Cutan Aesthet Surg 2012; 5: 222–5.
  1. 6. Yavuzer R, Başterzi Y, Sari A, Bir F, Sezer C. Chondroid syringoma: A diagnosis more frequent than expected. Dermatol Surg2003; 29: 179–81.

Multiple Choice Questions

Which of the following adnexal tumours is histomorphologically similar to mixed tumours (pleomorphic adenoma) arising in salivary glands?

  1. Chondroid syringoma
  2. Cylindroma
  3. Eccrine poroma
  4. Syringoma
  5. Trichoepithelioma

Answer: A

 

Which of the following may indicate malignant transformation?

  1. Extension into subcutis
  2. Multiple lesions
  3. Cellular atypia and necrosis
  4. Loss of myoepithelial cells
  5. Recurrence

Answer: C

 

What is the preferred management of chondroid syringomas?

  1. Discharge, no follow up required
  2. Observation
  3. Surgical excision with negative margins
  4. Laser treatment
  5. Topical treatment

Answer: C

 

 

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