What are the
signs and symptoms of primary cutaneous ALCL?
Primary cutaneous ALCL is a T-cell tumor of the skin. The appearance of the tumor varies among patients from a small raised discolored papule to a larger tumor. Most cases have just a single lesion but some patients may have several lesions and rarer cases may have generalized involvement of the skin. Occasionally, lesions may ulcerate.
Primary cutaneous ALCL must be differentiated from a condition which may initially appear very similar; lymphomatoid papulosis (LyP). The lesions of LyP may look very similar to primary cutaneous ALCL. Additionally, both can look very similar microscopically and both express a special protein called CD30 when tested in the laboratory. LyP distinguishes itself from primary cutaneous ALCL by its clinical course. LyP lesions usually regress without treatment. New LyP lesions may recur but these too will usually regress again without treatment. Spontaneous regression of primary cutaneous ALCL, however, is not typical though it does sometimes occur.
Primary cutaneous lymphoma must also be differentiated from systemic ALCL. Systemic ALCL is a more serious condition affecting other organs of the body beyond the skin.
How is primary cutaneous ALCL diagnosed?
The diagnosis of primary cutaneous ALCL is first made based on the clinical appearance of the lesion(s) and the history of the disease. Confirmation of the diagnosis is made by biopsy of the lesion and examining it microscopically. Laboratory investigations indicating that the cells express CD30 (a protein found on the surface of ALCL cells) is necessary to support the diagnosis. Because the prognosis and management of primary cutaneous and systemic ALCL are different, it is important to confirm that patients presenting with what looks like cutaneous ALCL do not have disease involvement beyond the skin. Careful medical examination and radiological investigation is necessary to rule out spread to other organs. Tumor cells should also be examined to confirm that they do not carry a particular genetic mutation
(t2;5 translocation) found in approximately 50% of systemic ALCL but
that is generally not seen in primary cutaneous disease. Because they do not have this mutation, they do not produce an enzyme called ALK. Primary cutaneous ALCL is therefore generally ALK-negative. |
