Leukemia Cutis

Definition: Leukemia cutis (LC) is a rare condition that refers to cutaneous infiltration of neoplastic leukocytes due to peripheral leukemia. 

Etiology: The etiology of any leukemia can be attributed to genetic and environmental risk factors that promote the expression of neoplastic cells. The proposed etiology of LC involved mechanisms of various chemokines and molecular expression on leukemic cells mediating their migration to the skin through skin0 selective homing processes. Environmental risk factors include benzene exposure, ionizing radiation, viral and alkylating agents. Aneuploidy of chromosome 8, translocation of chromosome 3 and (6;9) have been observed in patients with LC. It has been reported that all-trans retinoic acid to treat promyelocytic leukemia may increase the risk of cutaneous involvement.

Epidemiology: Exact data on the incidence and specific predilections of LC are unknown. It is believed that LC may affect approximately 3% of individuals with leukemia. However, individuals with adult T- cell leukemia/ lymphoma are more likely to develop LC. Up to 30% of children with congenital leukemia are more likely to develop LC. The subtypes of leukemia that commonly affect the skin are chronic lymphocytic leukemia (CLL) and acute myeloid leukemia (AML). Cutaneous involvement and the development of chloromas are typically indicative of advanced illness.

Signs: LC clinical presentation varies, and may be localized or disseminated and occur alone or in combination on any skin site. LC lesions favor previous sites of injury. LC lesions often appear as firm papules, nodules and plaques that are firm or rubbery in consistency. They may range in color from skin- coloured to erythematous to violaceous. In rare cases yellow, blue and gray lesions may be observed. LC lesions may also present with erythroderma, annular erythema, purpura, petechiae, ulceration, gingivitis/ gingival hyperplasia (AML). in infants, LC is a cause of “blueberry muffin syndrome”

Symptoms: LC lesions are usually not purritic or tender.

Differentials:  Lymphoma and pseudolymphoma, metastatic solid tumors, pyoderma gangrenosum, urticaria, vasculitis

Diagnosis: LC[1]  must be diagnosed using a skin biopsy, which will reveal a diffuse infiltration of malignant leukocytes in the dermis of the skin. Further histochemistry may reveal the specific cell type involved.

Treatment: Care of LC is directed towards addressing the underlying leukemia. Treatment includes electron beam, therapy, localized radiation and phototherapy.

References:

1.     Parsi M, Go MS, Ahmed A. Leukemia Cutis. In: StatPearls. Treasure Island (FL): StatPearls Publishing; July 17, 2023.

2.     Leukemia cutis | DermNet. dermnetnz.org. https://dermnetnz.org/topics/leukaemia-cutis