Derm Dx: An asymptomatic purplish bump - Clinical Advisor

Derm Dx: An asymptomatic purplish bump

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  • Dermatofibroma1_0214DermDx

  • Dermatofibroma2_0214DermDx

A 45-year-old woman complains of a purplish bump on the back of her left arm. She denies prior trauma. The lesion is asymptomatic. On physical exam, the papule displays the “dimple sign.”

Dermatofibromas, also called fibrous histiocytoma or sclerosing hemangioma, clinically present as benign, slightly raised, indurated, hyperpigmented papules with a shiny or keratotic surface. The color ranges from violaceous to brown.Dermatofibroma lesions display a predilection for the lower extremities. Although typically...

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Dermatofibromas, also called fibrous histiocytoma or sclerosing hemangioma, clinically present as benign, slightly raised, indurated, hyperpigmented papules with a shiny or keratotic surface. The color ranges from violaceous to brown.

Dermatofibroma lesions display a predilection for the lower extremities. Although typically asymptomatic, pruritus and pain can occur in some patients. The etiology of dermatofibromas is currently unknown, although it is suspected to occur after an insect bite or trauma to the area.

Upon examination, if a dermafibroma is pinched it will form a characteristic “dimple sign.” On histology, the epidermis is found to be hyperplastic and hyperpigmented, whereas the dermis shows a nodular proliferation of spindle cells. 

Diagnosis & Treatment

Dermatofibromas can be recognized by the lesion diameter, it’s slow growth and the characteristic “dimple sign” when pinched.  If the diagnosis is in question, a biopsy of the lesion may be taken for confirmation.

Treatment is usually not necessary, because dermatofibromas are benign and asymptomatic. The patient may request surgical excision to confirm the diagnosis, for cosmetic reasons, or due to frequent irritation of the lesion from daily activities, such as shaving.

If a patient requests the lesion be removed for cosmetic purposes, he or she should be informed of the possibility that the resulting scar may become more unsightly than the original dermatofibroma.

Other answer choices

Dermatofibrosarcoma protuberans is a malignant tumor that typically presents as an indurated flesh colored, purplish or reddish-brown plaque that develops nodules. The lesions are usually one to several centimeters in diameter and are most commonly located on the trunk of young to middle aged adults (50%-60% of the time). However, they can also be seen on the proximal extremities (20%-30%) and on the head and neck (10%-15%). 

Mohs surgery is the best course of treatment since it has a significantly lower rate of recurrence than standard surgical resection. Dermatofibrosarcoma protuberans has a low metastatic potential (approximately 5% of cases), although the chance of it metastasis increases after multiple local recurrences.

Atypical fibroxanthomas are malignant neoplasms that characteristically present as erythematous, rapidly growing, dome-shaped nodules on the face and neck of elderly patients with sun-damaged skin. The lesion, which has a predilection for male patients, typically has a diameter of 1-2 cm and may be eroded or ulcerated. 

Prognosis for atypical fibroxanthomas is generally good, as they rarely metastasize. Certain symptoms, such as necrosis, may be indicative of a lesion with higher metastatic potential. Surgical excision is the recommended course of treatment, with Mohs surgery having the lowest recurrence rates. Recurrence rates are approximately 5%.

Pseudolymphoma, also called cutaneous lymphoid hyperplasia or lymphocytoma cutis, typically presents as a benign, singular, erythematous to violaceous lesion that may be induced by a variety of stimuli such as medications, infections, or tattoos.  The lesion is prone to appear on the face or upper trunk of adults, although it has been observed in all ages.

Stephen Curtis, BS, is a graduate of Texas A&M University. 

Adam Rees, MD, is a graduate of the University of California Los Angeles School of Medicine and a resident in the Department of Dermatology at Baylor College of Medicine also in Houston.

References

  1. Bolognia J, Jorizzo JL and Schaffer JV. “Chapter 116: Fibrous and Fibrohistiocytic Proliferations of the Skin and Tendons.” Dermatology. Philadelphia, Pa.: Elsevier Saunders, 2012. Print.
  2. Bolognia J, Jorizzo JL and Schaffer JV. “Chapter 121: Other Lymphoproliferative and Myeloproliferative Diseases.” Dermatology. Philadelphia, Pa.: Elsevier Saunders, 2012. Print.
  3. Goldsmith L, Katz SI, Gilchrest BA et al. “Chapter 66: Dermal Hypertrophies and Benign Fibroblastic/Myofibroblastic Tumors.” Fitzpatrick’s Dermatology in General Medicine. New York: McGraw-Hill Medical, 2012. Print.
  4. Goldsmith L, Katz SI, Gilchrest BA et al. “Chapter 125: Malignant Fibrous, Fibrohistiocytic, and Histiocytic Tumors.” Fitzpatrick’s Dermatology in General Medicine. New York: McGraw-Hill Medical, 2012. Print.
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