| Abstract |
73 yo man with post radiation vertical rectangular plaques on lower back . |
Patient |
|
Duration |
one week |
Distribution |
Lower back |
| History |
Our patient is a pleasant 73-year-old male with a history of metastatic prostate cancer who presented with a non-pruritic, non-tender rash for 1 week across his lower back. He is currently receiving external beam irradiation with 7 beams entering the lumbar spine from distinct angles, docetaxel and an experimental regimen of dasatinib vs. placebo. He was last seen for the treatment of herpes zoster across his left flank and abdomen. The patient also reports a remote history of stress-induced psoriasis 40 years ago.
|
| Physical Examination |
There are approximately 6 well-demarcated, vertically oriented erythematous rectangular plaques with hyperkeratosis and silver scaling. No signs of impetiginization or excoriations are noted. There is also violaceous hyperpigmentation along the distribution of his previous herpes zoster, but no evidence of vesicles or re-activation.
|
| Images |
|
| Laboratory Data |
nil |
| Histopathology |
nil |
| Diagnosis |
A diagnosis of psoriatic koebnerization vs radiation recall dermatitis (RRD) was made |
| Reason for presentation |
Triamcinolone 0.1% ointment BID was prescribed. The patient was called one week post-presentation and he reported marked improvement of his eruption. He stated that the plaques continued to be asymptomatic but that they had become less palpable. |
| Questions |
This patient received external beam radiation therapy for bony metastasis of his prostate cancer. The therapy consisted of seven distinct vertical beams of radiation which penetrated the lumbar spine at distinct angles. The radiation oncologist confirmed that the distribution of the patient’s lesions were in the same areas where he received the beam irradiation.
RRD tends to appear hours to days after first exposure to a triggering chemotherapeutic agent which can be weeks to years after the initial radiation exposure. Our patient commenced treatment with docetaxel approximately one month after receiving his radiation treatment. He presented with his current findings approximately one month after the initiation of docetaxel.
RRD can present on a spectrum from a mild erythema with dry, pruritic desquamation to a similar presentation plus pain, edema, vesiculation to a severe necrosis, ulceration and hemorrhage. Clincally, the patient’s lesions are psoriasiform. There was no evident desquamation, vesiculation, impetiginization nor excoriations (to suggest that the eruption is symptomatic).
In approximately 25% of psoriasis patients, koebnerization can be induced by various forms of cutaneous injury, such as sunburn, external radiation, morbilliform drug eruptions or viral exanthems. The koebnerization typically takes 2-6 weeks to appear after the inciting event. Our patient received radiation treatment and presented with an eruption of one weeks' duration 6 weeks later, approximately fitting the characteristic time frame of the koebner phenomenon.
Definitive diagnosis can only be made via biopsy where RRD would demonstrate non-specific inflammatory changes in contrast to psoriatic koebnerization which would demonstrate the characteristic histological psoriasiform changes. Given the clinical appearance, distribution, evolutionary time course and the asymptomatic nature of the eruption, we treated the eruption as psoriatic koebnerization. The patient has responded well to treatment. |
| References |
- Bolognia JL. Jorizzo JL. Rapini RP, editors. Dermatology. 2nd ed. Spain: Mosby; 2008.
- Camidge R, Price A. Characterizing the phenomenon of radiation recall dermatitis. Radiother Oncol. 2001 Jun;59(3):237-45. Review. PubMed PMID:11369064.
- Charalambous H, Bloomfield D, Psoriasis and radiotherapy; exacerbation of psoriasis following radiotherapy for carcinoma of the breast (the koebner phenomenon). Clin Oncol 2000;12:192-3.
- Schreiber GJ, Muller-Runkel R. Exacerbation of psoriasis after megavoltage irradiation. Cancer 1991;67:588-9.
- Tomlinson MJ. Psoriasis and radiotherapy. Clin Oncol 2001;13:145-6.
|
| Keywords |
radiation recall dermatitis, koebnerization, psoriasis. |
| Comments from Faculty and Members |
|
