Dermatology is a growing clinical area in primary care settings. A 2001 study found that 36.5% of all patients had a chief complaint of skin disease when visiting their primary care provider.1 Many skin conditions are benign, in the sense that they are not life-threatening. If a patient presented to your office with a pruritic, erythematous patch or plaque on his or her body, would you know how to approach it and what your differential diagnoses would be? The following case study and discussion is about a rare but potentially fatal skin disorder that presents in this manner.
A 58-year-old white man presented to the dermatology office with a 3-year history of progressively worsening scattered pruritic eruptions over various areas of his body. The lesions never develop on his scalp or palms. The patient had seen two dermatologists to reach and confirm a diagnosis. A shave biopsy led to a diagnosis of mycosis fungoides, a type of lymphoma.
The patient was treated with a topical steroid cream consisting of triamcinalone 0.1% (Kenacort). This caused a burning sensation in the lesions, so the patient stopped using it. Based on the patient's history and workup below, would you know what would you do next?
The most important part of any patient's office visit is gathering the history of present illness and the general medical history. This patient's history of present illness was as discussed above. The only significant medical history was anaplastic large cell lymphoma, which had been in remission for 5 years. His original presentation of lymphoma was as a swollen left axillary lymph node. He was treated with chemotherapy, radiation and excision of that mass.
Because of his history, his workup for mycosis fungoides was extensive. A 5-mm punch biopsy from the thoracic area was performed to confirm diagnosis. A chest x-ray was ordered to rule out any possibility of metastases to the lungs. A cytology blood flow study was also needed to look for Sézary cells. Sézary syndrome is another form of cutaneous T-cell lymphoma, and it must be differentiated from mycosis fungoides. A complete blood count with blood smear can also look for these particular cells. This patient's chest x-ray was clear. His blood smear did not show Sézary cells. The punch biopsy confirmed mycosis fungoides.
The Disease Process
Mycosis fungoides is a specific diagnosis in a larger spectrum of skin lymphomas known as cutaneous T-cell lymphomas (CTCL).2 These lymphomas involve a proliferation of malignant T-cells on or below the skin's surface. T-cells occur normally in the body. They help with immune function regulation and assist in fighting infection.2 Although mycosis fungoides is visible on the skin's surface, the cancer enters the subcutaneous tissue and can even spread deeper. In approximately 10% of cases, it spreads to the lymph nodes and internal organs.3 Mycosis fungoides has been described as a "cancer that sounds like a fungal infection, but kills like a cancer."4
Diagnosis is difficult because mycosis fungoides is not a common differential for primary care providers. It is not a fungal infection at all. The disease was discovered in 1806 by a French dermatologist, Jean Louis Albert. He called it "mycosis fungoides" because of the mushroom-like (fungal) appearance of the lesions on some patients.5 The disease often presents as a scaly, reddish plaque that can be misdiagnosed for psoriasis, eczema or any atopic dermatitis. It can also present in a patch or tumor stage, instead of a plaque.3 Opportunity for misdiagnosis exists as a result of the similarities between mycosis fungoides and these conditions.
Eczema and mycosis fungoides both can present in a papular or plaque stage that is erythematous and pruritic. Mycosis fungoides can also mimic psoriasis because it commonly appears in a plaque form and is pruritic. History plays a part because common elements often exist in the presentation. A patient with eczema can present with a history of allergies, asthma or other skin sensitivities. A history of lymphoma can lead the provider to suspect mycosis fungoides more quickly since it is a form of lymphoma. It is important to note that mycosis fungoides is not inevitable in all lymphoma cases; there is a correlation only. Other risk factors that are being researched are environmental factors such as drug use, infection and exposure to chemicals or radiation.6
It is important to stress that if mycosis fungoides is suspected, a biopsy must be done because this is the only way a definitive diagnosis can be made.7,8
Differential diagnosis for this sort of skin eruption includes psoriasis, eczema and atopic dermatitis.3 It can be difficult to see particular differences in presentation when the skin is scaly. Atopic dermatitis or eczema usually presents as a maculopapular lesion (raised and rounded) or a plaque (raised and widespread) that is red, gray or brown in nature. It can be pruritic (itchy), and the skin is usually thickened and dry.9 Due to the inflammatory nature of this condition, people with allergies and asthma are more prone to atopic dermatitis.9 Mycosis fungoides can be difficult to distinguish. It can present in many different forms and mimic benign skin disorders. Based on the patient's history (specifically a malignancy), a biopsy should be done.
Psoriasis presents as a red patch with silver scales. It can also be pruritic and somewhat painful. The skin is also usually dry and cracked.10 When a plaque is pulled off and away from the skin, pinpoint bleeding may be present underneath. This is known as the Auspitz sign, and it is fairly diagnostic of psoriasis.11 Lesions from mycosis fungoides do not usually bleed.
Treatment and Outcomes
The treatment for mycosis fungoides is fairly standardized. Topical agents work well for less extensive disease because they provide a more targeted therapy. A topical agent such as imiquimod (Aldara) 5% cream is a chemotherapeutic agent that can produce a 50% clearance rate.12,13 Another topical chemotherapeutic agent used in mycosis fungoides is chlormethine (nitrogen mustard).12.
Retinoids are a derivative of vitamin A and are in the same drug class as steroids. They work against mycosis fungoides by regulating and interfering with several physiologic processes. They affect the growth, development and life span of cells.14
Systemic interferon is used to treat widespread cases of mycosis fungoides. Interferon alpha-2b is a protein released by the body to fight viral infections. It is used in the treatment of cancer to help stimulate the immune system to mount a stronger response to the foreign tissue. This medication is delivered as a subcutaneous injection.8,15
Psoralen with ulraviolet light therapy (PUVA) has shown success against mycosis fungoides.4 Psoralen helps the skin absorb the ultraviolet light. The patient is exposed to UVA light for approximately 20 to 30 minutes, three times a week. UVA light is used because it penetrates deeper into the skin than UVB. Side effects of this treatment can include sunburn, blistering, tanning and, on rare occasions, skin cancer (in association with more than 250 treatments).15
The patient described in the case study had a treatment plan that included some of the discussed methods. Prescribed medications were methotrexate (Rheumatrex) 25 mg IM weekly and folic acid 1 mg oral daily. He underwent a complete blood count and renal and liver panel every 2 weeks for 2 months, then monthly. Methotrexate is a chemotherapeutic agent that has shown success in treating mycosis fungoides. Liver function should be closely monitored while on this medication.8 The patient in this case study had a fairly typical presentation of mycosis fungoides, including a history of lymphoma. Biopsy confirmed his diagnosis, and his treatment is ongoing.
Mycosis fungoides can be easily misdiagnosed for a patch or plaque condition such as psoriasis or eczema. It is essential to gather a thorough patient history and consider all possible differential diagnoses. If you suspect this condition, referral to a dermatology specialist is essential. A skin biopsy is a necessary part of diagnosis. Patients can go several years with repeated erroneous biopsies before being correctly diagnosed.1
Sarah Kern is a adult nurse practitioner at Trihealth Senior Link in Cincinnati.
Lowell BA, et al. Dermatology in primary care: Prevalence and patient disposition. J Am Acad Dermatol. 2001;45(2):250-255.
Huber MA, et al. Management of refractory early-stage cutaneous T-cell lymphoma. Am J Clin Dermatol. 2006;7(3):155-169.
Longo DL. Watch out, MF! Blood. 2007;110(6):1708-1709.
Osman MA, et al. Mycosis fungoides: historical aspects. Sudan J Dermatol. 2007;5(1): 22-27
Wohl Y, Tur E. Environmental risk factors for mycosis fungoides. Curr Prob Dermatol. 2007;35:52-64.
Horwitz SM, et al. Review of the treatment of mycosis fungoides and Sezary syndrome: a stage-based approach. J Natl Compr Canc Netw. 2008;6(4):436-442.
Sabri AA, Qayyum MA. Psoriasis with Auspitz Sign. CMAJ. 2006;175(1):31.
Soler-Machin J, et al. Imiquimod in treatment of palpebral mycosis fungoides. Arch Soc Esp Oftalmol. 2006;81(4):221-223.
Deeths MJ, et al. Treatment of patch and plaque stage mycosis fungoides with imiquimod 5% cream. J Am Acad Dermatol. 2005;52(2):275-280.
Zhang C, Duvic M. Treatment of cutaneous T cell lymphoma with retinoids. Dermatol Ther. 2006;19(5): 264-271.
Avilés A, et al. Interferon and low dose methotrexate in refractory mycosis fungoides/Sézary syndrome. Cancer Biother Radiopharm. 2007;22(6):836-840.