An unusual cutaneous T cell lymphoma presenting as leonine facies

ARTICLE

The term cutaneous lymphomas comprises a heterogenous group of lymphocytic malignancies that preferentially involve the skin [1]. Out of all primary cutaneous lymphomas more than 95% are supposed to belong to one of the disease entities included in the EORTC Classification for Primary Cutaneous Lymphomas [2]. But it is important to recognize that some cases of cutaneous lymphoma do not fit into one of the well-recognized or provisional categories. We report a case of an unusual and unclassifiable cutaneous T cell lymphoma (CTCL) with the clinical picture of a leonine facies as the only skin lesion appearing during the first 5 years of the disease.

Case report

A 64-year-old Caucasian male presented with a two-year history of an itchy erythematous eruption on the face. On examination the skin of his face was thickened and indurated with deep furrows, moderate erythema and a sparse fine scaling, resembling chronic actinic dermatitis, particularly actinic reticuloid (Figs. 1 and 2). He had a personal history of high cumulative sun exposure, but he denied any history of light intolerance.

Atopy screening, patch test and photopatch test were negative. The minimal erythema doses (MED) of ultraviolet (UVA and UVB) were within normal ranges. The photoprovocation tests on the upper back with ascending doses of up to 30 J/cm² UVA and up to 1.5 MED UVB as well as a combined UVA/B irradiation were all negative.

The blood count showed a normal red cell count and a slight leucocytosis (11,400 x 10³/mul), in the differentiation 14% atypical lymphocytes with indented (cerebriform), partly clover-leef form nuclei and basophil cytoplasm (Fig. 3). The cells were of a CD2⁺, CD3⁺, CD4⁺, CD5⁺, CD 29⁺ and CD7^­ phenotype. Test for HTLV-1 (EIA IgG) was negative, CD4/CD8 ratio 10.1.

Further laboratory investigations of the blood showed an elevated ESR (22/45), slightly elevated CrP, LDH, IgG, a low level IgA paraproteinemia type lambda and a thymidine kinase of 11 (ref. < 4) U/l.

A biopsy specimen of the skin revealed a dense, partly diffuse, partly perivascular and periadnexial dermal infiltrate of small to medium-sized pleomorphic atypical lymphocytes with chromaffin nuclei and small cytoplasm (Fig. 4), showing several mitoses. Focal migration of atypical lymphocytes into the epidermis forming small lymphocytic (Pautrier's) microabscesses was seen (Fig. 5). Immunohistochemically the atypical lymphocytes had a CD2⁺, CD3⁺, CD4⁺, CD5⁽⁺⁾, CD7^­, CD8^­, CD19^­, CD22^­, CD23^­, CD25⁽⁺⁾, CD45R0⁺ and CD56^­ phenotype.

A bone marrow biopsy showed a sparse diffuse infiltration by small to medium-sized lymphocytic cells with pleomorphic, occasionally deeply indented, nuclei (Fig. 6) and an immunohistochemically irregular CD3 positivity, amounting to approximately 10% of all nucleated cells.

Physical examination revealed no additional pathological findings. Chest X-ray, ultrasonography of the abdomen and of the lymph node regions and computertomography of the trunk were without pathological findings.

The diagnosis of an atypical mycosis fungoides (MF)-like CTCL with transformation into pleomorphic small/medium sized T cell lymphoma (TCL) was made.

Treatment with local corticosteroids and, because of the patient's refusal to try oral psoralen-UVA (PUVA) therapy, retinoids was initiated, but this increased the itch. Two courses of a combined UVA/UVB phototherapy brought temporary improvement, but still no remission. Blood controls continuously revealed constant findings. The further course of the disease was variable without progression for three more years. Then gradually patchy lesions resembling those in MF developed at different sites of the body (Fig. 7), exhibiting the same histological appearances as the primary skin lesions in the face. Neither had peripheral blood values worsened, nor was an involvement of the lymph nodes evident. Another bone marrow biopsy was rejected by the patient at that time. Treatment with extracorporeal photochemotherapy (ECP) was started. After 12 months and 14 cycles of ECP the patient responded well, resulting in partial remission of the disseminated skin lesions and significant improvement of the facial skin symptoms and the itch. The involvement of the peripheral blood has completely disappeared and a bone marrow biopsy has now failed to show an infiltration by the malignant lymphoma.

Discussion

We report a case of an unclassifiable CTCL, with a clinical picture resembling that of chronic actinic dermatitis and tumor cells resembling those in pleomorphic small/medium-sized TCL as well as those of classical MF, Sezary syndrome. The extracutaneous involvement of the peripheral blood and bone marrow, but not of the peripheral lymph nodes was also atypical.

Chronic actinic dermatitis is excluded by the absence of photosensitivity [1]. For a pleomorphic small/medium-sized primary CTCL, which presents with single red-purplish cutaneous nodules or tumors, the type of skin lesions is unusual [1, 3]. Furthermore the epidermotropism of the lymphocytic cells as well as the indolent clinical behaviour in spite of an involvement of the peripheral blood do not conform to pleomorphic small/medium-sized CTCL [2-5]. The latter characteristics again, together with the small indented cerebriform ("Sezary"-like) lymphocytic cells seen in the peripheral blood and in the bone marrow, resembled MF, respectively Sezary syndrome. However, the simultaneous occurrence of pleomorphic tumor cells and the atypical extracutaneous organ involvement of the bone marrow and peripheral blood without lymphadenopathy are incompatible with classical MF. Since the Sezary syndrome is defined by erythroderma and generalized lymphadenopathy [6] it can be excluded in this case. Chronic lymphatic T cell leucemias (T-CLL) are frequently associated with an infiltration of the skin, occasionally appearing with the clinical picture of leonine facies, but a T-CLL is largely ruled out by the occurrence of Sezary-like cells of a CD7^­ and CD8^­ phenotype in the peripheral blood, and moreover by the absence of high white cell count, lymphadenopathy or splenomegaly [7].

Thus, based on clinical, histological and immunological criteria the diagnosis of an atypical intermediate CTCL exhibiting signs of pleomorphic small/medium-sized TCL and, preponderantly, of MF characterizes the disease adequately. This is confirmed by the development of patches and plaques resembling MF in the later course of the disease.

Whereas cutaneous B-cell lymphomas present preferentially on the head and neck, cutaneous T cell lymphomas manifest on the face late in the course of the disease [1]. Likewise in classical MF an involvement of the head and neck skin occurs only during disease progression at stage III, sometimes also with the clinical picture of leonine facies [8], occasionally associated with photosensitivity [9]. But a primary manifestation with leonine facies-like skin lesions strictly restricted to the face and neck without spreading or dissemination after several years would be very unusual for MF. Only one case clinically similar to the present one has been published by Neill and du Vivier as 'mycosis fungoides mimicking actinic reticuloid', also without photosensitivity [10]. Yet in contrast to our patient disseminated patchy lesions typical of MF had preceded the facial infiltration and remained present.

Another striking atypia in the present CTCL is an involvement of peripheral blood and bone marrow without the involvement of peripheral lymph nodes, even if ­ without lymph node biopsy ­ the latter is not absolutely excluded. Whether in this case the skin involvement is a primary or secondary manifestation of the lymphoma cannot be distinguished. According to the EORTC classification, primary cutaneous lymphomas include only non-Hodgkin lymphomas presenting in the skin with no evidence of extracutaneous disease at the time of diagnosis and within the first six months after diagnosis, except for classical MF or Sezary [2]. Hence, the present case can only be categorized according to the International Lymphoma Study Group as an unspecified peripheral TCL [7]. However, as it shares features with MF and manifests predominantly in the skin, the cutaneous origin of the lymphoma is highly probable, considering that the diagnosis of lymphoma with cutaneous and extracutaneous involvement was first made three years after the onset of the disease.

CONCLUSION

In conclusion, the question as to whether the present case is a rare clinical variant of MF, which has so far not been included in the EORTC Classification for Primary Cutaneous Lymphomas, or a unique case of unclassified transitional CTCL with features of both pleomorphic small/medium-sized TCL and MF, as the authors maintain here, remains to be answered.

Article accepted on 14/2/00

Acknowledgements

We thank Professor Karl Lennert, Lymphnode Registry, Institute of Pathology, University of Kiel, Germany, for his consulting review of the skin biopsy.

REFERENCES

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