Two well-defined 6-mm nodules on a teenager's arm - Clinical Advisor

Two well-defined 6-mm nodules on a teenager’s arm

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A 13-year-old girl presents with a cystic lesion that has been on her forearm for several years. Concerned about the lesion, she reports that it may have grown slightly larger in the past year and it is intermittently painful. More recently, a second similar lesion has appeared in close proximity. She denies any other suspicious lesions elsewhere on her skin. Her family history is negative for skin cancer, and she reports no other medical conditions. Physical examination reveals two well-defined 6-mm nodules that are rubbery, slightly tender, and pink on the right proximal ventral forearm. The overlying skin is intact, and there is no associated adenopathy. 

Spiradenoma, also known as eccrine spiradenoma, spiroma, and cystic epithelioma of the sweat gland, is an uncommon, yet mostly benign, skin tumor of eccrine sweat gland origin. The benign lesion of spiradenoma typically presents as a single deep, gray, pink,...

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Spiradenoma, also known as eccrine spiradenoma, spiroma, and cystic epithelioma of the sweat gland, is an uncommon, yet mostly benign, skin tumor of eccrine sweat gland origin. The benign lesion of spiradenoma typically presents as a single deep, gray, pink, or blue dermal nodule, approximately 1 cm in size. The head, neck, and trunk are the most common sites of presentation; spiradenomas may also appear on the extremities, in which case they are typically on the ventral aspect.1

Although it usually appears as a solitary lesion, occasionally—as was the case with our patient—two or more lesions may appear. Multiple lesions may present in a linear, grouped, or Blaschkoid distribution. Although a spiradenoma can occur at any age, the most frequent population affected is young adults aged 15 to 35 years.2 Many patients describe a history of slow growth and intermittent pain associated with the lesion.

Malignant transformation of spiradenoma is extremely rare,3 but when it occurs, it can be aggressive, with a high mortality rate. In addition, malignancy usually develops from a long-standing existing lesion.4

The cause of this eccrine sweat gland tumor is not well known, although it seems to be caused by a defective tumor suppressor gene. In rare cases, it can present in association with Brooke-Spiegler syndrome, an autosomal dominant condition involving the appearance of multiple skin tumors starting in early adulthood.5 Patients with Brooke-Spiegler syndrome also manifest with trichoepitheliomas and cylindromas, and they are at risk for salivary gland tumors.

The differential diagnosis is vast and often varies based on area of involvement. Painful tumors to consider include neuroma, glomus tumor, leiomyoma, angiolipoma, neurilemmoma, and dermatofibroma.6 Other clinical entities that may mimic spiradenoma include pilar cyst, pseudolymphoma, and metastatic carcinoma.

Skin biopsy, ideally a punch biopsy, is necessary for a correct diagnosis. Histologically, a spiradenoma appears as a well-circumscribed dermal nodule with sharply marginated lobules and a delicate fibrous capsule that is not connected to the epidermis. Nests of basophilic cells with small dark nuclei are observed, and sometimes large pale cells and duct-like differentiation are present in the center of the lesion. Often a lymphocytic infiltrate is present.

The only known acceptable treatment for spiradenoma at this time is surgical excision of the lesion. Recurrence after complete excision is rare. If patients choose not to have the lesion excised, it must be closely observed to detect any signs of malignant transformation. In addition, patients with the diagnosis of spiradenoma should undergo a full skin check to evaluate for other skin tumors and to rule out the presence of Brooke-Spiegler syndrome. One study has described carbon dioxide laser for treatment of multiple lesions.7 In the rare scenario of malignancy, treatment consists of chemotherapy and radiation.

For the patient in our case, a punch biopsy specimen sent for histopathologic examination revealed the diagnosis of spiradenoma. The patient, with consent from her mother, chose to undergo excision of both lesions. In addition, she had a full skin examination that did not identify any other suspicious skin lesions. Excision of the lesion with adequate margins was performed without complications.

Esther Stern, NP, is a family nurse practitioner at Advanced Dermatology & Skin Surgery, P.C., in Lakewood, N.J.

References

  1. James WD, Berger TG, Elston DM. Andrews’ Diseases of the Skin: Clinical Dermatology. 11th ed. Philadelphia, PA: Saunders-Elsevier; 2011.
  2. Sahin MT, Öztürkcan S, Bilaç C, Tan A. Dermoscopy of eccrine spiradenoma: a case report. J Am Acad Dermatol. 2015;72(5 suppl 1):AB88.
  3. Chow W, Griffiths M. A malignant eccrine spiradenoma of the scalp. BMJ Case Rep. 2014. doi: 10.1136/bcr-2013-202524
  4. Jesús Fernández-Aceñero M, Manzarbeitia F, José Mestre de Juan M, Requena L. Malignant spiradenoma: report of two cases and literature review. J Am Acad Dermatol. 2001;44(2):395-398.
  5. Paller AS, Mancini AJ. Hurwitz Clinical Pediatric Dermatology. 4th ed. Philadelphia, PA: Saunders-Elsevier; 2011.
  6. Naversen DN, Trask DM, Watson FH, Burket JM. Painful tumors of the skin: “LEND AN EGG.” J Am Acad Dermatol. 1993;28(2 Pt 2):298-300.
  7. Martins C, Bártolo E. Brooke-Spiegler syndrome: treatment of cylindromas with CO2 laser. Dermatol Surg. 2000;26(9):877-880; discussion 881. 
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