[T-cell prolymphocytic leukemia: potential diagnostic pitfalls]

BACKGROUND

Sezary syndrome (SS) presents clinically as erythroderma, which may be pigmented, and pruritic, associated with peripheral lymphadenopathies. Erythroderma may also occur in a broad range of reactive and malignant conditions including T-cell prolymphocytic leukemia (T-PLL). We report a case initially diagnosed as SS but ultimately diagnosed as T-PLL based upon skin involvement.

CASE REPORT

A 70-year-old man was referred by his hematologist for management of SS. Physical examination revealed lymphadenopathies and mild diffuse erythema without infiltration. His WBC count was elevated at 8.3 G/L. A peripheral blood smear showed Sezary-like cells. Flow cytometry of peripheral blood revealed prolymphocytic T-cells staining positively for CD2, CD3, CD4 and CD7. Cytogenetic studies showed chromosomal abnormalities in terms of number and structure with missing chromosomes 6 and13, as well as deletion of chromosome 17. Finally, a diagnosis of T-PLL was made. Pentostatin was initiated pending treatment with alemtuzumab, but the patient's overall condition deteriorated rapidly and he died 10 days later.

DISCUSSION

Diagnosis of LPLT is based upon a number of factors. In the case presented herein, the clinically atypical nature of the skin lesions prompted the dermatologist to review the diagnosis. The morphology of the circulating T-lymphocytes and their immunologic and phenotypic characteristics finally ruled out the diagnosis of Sezary syndrome, while their association with compatible cytogenetic anomalies enabled a diagnosis of prolymphocytic leukemia to be made instead.

CONCLUSION

Prolymphocytic leukemia involves complex differential diagnosis with regard to Sezary syndrome, posing potential pitfalls for hematologists and dermatologists.

[A rare cutaneous congenital sarcoma: plexiform fibrohistiocytic tumor]

We report the unusual case of a three-year-old girl which presented since birth a pigmented tumor of the left side 0.5cm in diameter. Surgical removal was decided given the hypothesis of a congenital naevo-cellular naevus. The histological study ended with the diagnosis of plexiform fibrohistiocytic tumor (PFHT). Two other congenital PFHT have been reported until now. PFHT is a rare mesenchymal neoplasm of intermediate malignancy, first reported by Enzinger and Zhang in 1988 which may be difficult to diagnose, because of its low frequency, particulary in congenital cases. It is important to distinguish it from others childhood cutaneous tumors (particulary plexiform neurofibroma, cellular neurothekeoma, infantile myofibromatosis, and fibrous hamartoma). The tumor has a high local recurrence rate and complete surgical resection of the tumor, with wider margins, is required.