Volume 25Number 4October 1991

take 6months). In our experience, approximately 50% ofperiungual warts treated with the C02 laser are com­pletely reepithelialized at 6 weeks. None of these caseswas infected. Although infection may be a complicationin a few CO2laser cases, periostitis or osteomyelitis didnot occur in this series or in any patients treated at theMayo Clinic.

The definition of power density is the wattage (deliv­ered to tissue) divided by 1r' r2(impact surface area). Toknow an accurate power density one must know the ex­act spot size at the treatment site. When using the C02laser in a defocused fashion, the surgeon's hand movesover the curvatures of thefinger at least slightly changingthe effective spot size. The spot size also changes as youvaporize tissue because the distance increases as the le­sion gets smaller. Unless the distance from the hand pieceto the treatedsite is exactly the same at all sites, there willbe variance in the impact surface area. Therefore thepower density will continually vary. if only slightly,Energy fluence = Power density X Time, adding thevariance ofspeed with which the surgeon works. The onlyfixed settings for the CO2laser are the wattage and thespot size at focality (dependent on the optics of the lensin the hand piece).

Randall K. Roenigk, MD. andMarcy L. Street, MDRochester, Minnesota

Sezary cell counts in treatment of the Sezarysyndrome

To the Editor: Armus et al. (J AM ACAD DERMATOL

1990;23:898-902) reported results with photopheresis inthe treatment of eight patients with cutaneous T celllymphoma (CTCL). Five of the patients had generalizederythroderma. However, no data are presented as toSezary cell counts in the five; thus they cannot be char­acterized as having either erythrodermic mycosis fungo­ides or the S6zary syndrome. Schechter et al. l reportedthat patients with CTCL with increased numbers ofatypical convoluted cells in the blood have a survival ratesignificantly inferior to those who did not. Itwould be.ofinterest to know whether the Sezary cell count, if ob­tained, changed in response to photopheresis therapy.

This query is also prompted by the observation ofEdelson et al.2that no significant changes were identifiedin the percentage of S6zary cells, total leukocyte counts,or in lymphocyte percentages in patients with CTCLtreated with photopheresis. By contrast, clinical improve­ment correlated with a decrease in the Sezary cell and to­tal leukocyte counts in patients with theSezary syndrome

Correspondence 731

treated with low-dose methotrexate.3 Clinical status andSezary cell counts were used to monitor patients with theSezary syndrome treated with low-dose chlorambucil andprednisone.4

Armus et al. state that in the report of Edelson et al.2

photopheresis produced improved survival for patientswith erythrodermic CTCL. However, in that report nosurvival data are provided. In fact, the authors clearlystate that the follow-up period was too short to assess thelong-term effect of photopheresis.

Later in their article Armus et al. provide follow-updata on the original group of patients ofEdelson et al.2Acomparison is made between the survival rate of theEdelson et al. group versus that ofCTCL patients treatedwith other therapies. The statement regarding othertherapies apparently is based on Fig. 7 in the review ar­ticle by Winkler and Bunn,s which presents survival dataon CTCL patients treated with combined modalities atthe National Cancer Institute. However, the curve for theNational Cancer Institute group includes onlystage II-IVpatients, whereas the group ofEdelson et al. also includesstage I patients.

Herschel S. Zackheim, MDDepartment ofDermatology

University ofCalifornia. San FranciscoSan Francisco, CA 94143

REFERENCES1. Schechter GP, Sausville EA, Fischmann AB, et al. Evalua­

tion of circulating malignant cells provides prognostic infor­mation in cutaneous T cell lymphoma. Blood 1987;69:841-9.

2. Edelson R, Berger C, Gasparro F, et al. Treatment of cuta­neous T-cell lymphoma by extracorporea1 photochemother­apy. Preliminary results. N Engl J Med 1987;316:297-303.

3. Zackheim HS, Epstein EH Jr. Low-dose methotrexate forthe Sezarysyndrome. JAM ACAD DERMATOL 1989;21:757­62.

4. Winkelmann RK, Diaz-Perez JL, BueChner SA. The treat­ment of Sezary syndrome. J AM ACAD DERMATOL 1984;10:1000-4.

5. Winkler CF, Bunn PA Jr. Cutaneous T-cell lymphoma: areview. CRC Crit Rev Oncol HematoI1983;1:49-92.

Reply

To the Editor: Three ofthe five patients in our study withcutaneous T cell lymphoma (CTCL) who had general­ized erythroderma and tested positive for S6zary cellsshowed no significant change in their Sezary cell countduring treatment with extracorporeal photochemother­apy. With respect to enhanced survival of the originalgroup treated by Edelson et al., reference number 8 wasinadvertently excluded from the text. This reference citesthe follow-up statistics of the original group. In the orig-