Role of slit skin smear examination in cutaneous T-cell lymphomas and other chronic dermatoses
B Bindu¹, Annamma Kurien², S D Shenoi¹,and Smitha Prabhu¹
Dermatology Online Journal 12 (3): 2

Abstract

The purpose of this study was to evaluate the utility of slit-skin smear examination in the diagnosis of various chronic dermatoses. The study included 24 patients with chronic dermatoses who presented to the skin outpatient department. Ten patients had idiopathic erythroderma, seven were diagnosed with airborne contact dermatitis, four had cutaneous T-cell lymphoma, two had chronic actinic dermatoses, and a single patient had panniculitis. Slit skin smears were obtained from all patients, stained with Leishman stain, and examined under microscope. Out of 24 patients, all four cases of cutaneous T-cell lymphoma showed abnormal cells suggestive of lymphomatous infiltration, two patients with airborne contact dermatitis showed reactive lymphocytes, and two idiopathic erythroderma cases showed numerous eosinophils in the smear. Slit skin smear examination is a simple rapid, decisive test in the diagnosis of cutaneous T-cell lymphoma. It is a useful screening test, especially in Sezary syndrome and diseases with specific skin infiltrate.

Introduction

Cytology of the skin is an extremely useful tool for case management in dermatology. Common cytological methods in dermatology include Tzanck smear (for diagnosis of vesiculobullous disorders and blistering viral diseases), skin scrapings (examination for fungi or mites), fine needle aspiration (evaluation of of masses, cysts, or large pustules), impression smears (evaluation of excised masses, biopsies, exudates, or transudates), and skin imprint cytology (evaluation for basal cell carcinoma) [1, 2, 3]. We currently use slit-skin smear with Ziehl Nielsen stain to demonstrate acid-fast bacilli in Hansen disease [4]. The objective of this study was to evaluate the utility of slit skin smear in various dermatoses.

Methods

We conducted a prospective study in the Department of Dermatovenereoleprology, KMC Hospital, Manipal over a 12 month period from March 2004 to February 2005. The study included 24 patients with chronic dermatoses of long duration. The patients were aged 21-73 years. There were 21 males and 3 females. The diseases included were as follows: idiopathic erythroderma (n = 10), airborne contact dermatitis (n = 7), suspected cutaneous T-cell lymphoma (n = 4), chronic actinic dermatosis (n = 2), and panniculitis (n = 1).

Table 1: relevant positive slit skin smear reports out of total number of cases

Figure 1
Normal slit-skin smear with Leishman stain

Procedure

Slit skin smears were taken from the most prominent lesions. After cleaning with alcohol, the area was grasped between the thumb and forefinger of the non-dominant hand until the site was blanched. A 5-mm long and 3-mm deep incision was made with Bard Parker No. 15 blade and the sides of the incision scraped to obtain tissue fluid and pulp. A smear was made on a clean glass slide, stained with Leishman stain, and examined under the oil-immersion objective of the microscope.

Results

Out of the ten idiopathic erythroderma cases, two showed numerous eosinophils in the smear; one of these cases later turned out to be hypereosinophilic syndrome. Of the seven airborne contact dermatitis cases, two showed reactive lymphocytes. All four cases (100 %) of cutaneous T cell lymphoma showed abnormal cells suggestive of lymphomatous infiltration. These cases were later confirmed by histopathology and immunophenotyping.

Figure 2	Figure 3
Figure 2. A 71-year-old man with erythematous infiltrated plaques and nodules (case 1)
Figure 3. Abnormal lymphoid infiltrate (× 400)

Figure 4	Figure 5
Figure 4. Leishman stain (× 400)
Figure 5. (× 1000)

Case 1—A 71-year-old man who presented with erythematous infiltrated plaques and nodules of 1-year duration, with aggravation for the past 4 months. Chemotherapy was deferred because of his age and co-morbid conditions such as diabetes mellitus and hypertension. He is being treated symptomatically.

Figure 6	Figure 7
Figure 6. A 49-year-old man with large-plaque parapsoriasis (case 2)
Figure 7. Abnormal lymphoid infiltrate (× 100)

Figure 8
Figure 8. Leishman stain (× 1000)

Case 2—A 49-year-old man, initially diagnosed with psoriasis, later developed large plaques that turned out to be cutaneous T-cell lymphoma on further evaluation. At the time of diagnosis malignant infiltration of lymph nodes had occurred. He was treated with CHOP regime and then switched to PUVA therapy; he showed only a partial response.

Figure 9	Figure 10
Figure 9. A 19-year-old woman with erythroderma (case 3)
Figure 10. Abnormal lymphoid infiltrate (× 100)

Figure 11
Figure 11. Leishman stain (× 1000)

Case 3—A 19-year-old woman presented with erythroderma of 3-months duration. Based on histopathology reports she was initially diagnosed with psoriasis and was improving with oral methotrexate. Later she developed purpuric, exfoliative plaques and nodules on the face and lower limbs. Repeat skin biopsy and histopathology and immunophenotyping clinched the diagnosis of cutaneous T-cell lymphoma. She expired 1 month after diagnosis.

Figure 12	Figure 13
Figure 12. A 31-year-old woman with erythroderma (case 4)
Figure 13. Leishman stain (× 100)

Figure 14
Figure 14. Leishman stain (× 400)

Case 4—A 31-year-old woman was diagnosed in 1997 with erythroderma associated with cutaneous T-cell lymphoma. She was given chemotherapy (CHOP regime). She improved, but 6 years she developed widely dispersed infiltrated plaques and nodules. Despite treatment with various chemotherapy regimes, she expired after a few months.

Conclusions

Diagnosis of cutaneous T-cell lymphoma requires histopathological evaluation, along with more accurate techniques such as immunophenotyping and T-cell receptor gene analysis [2, 3]. In this study we evaluated the accuracy of a simple, rapid,and cost effective technique, i.e., slit skin examination of the involved skin for abnormal lymphocytes for the preliminary diagnosis of cutaneous T-cell lymphoma. Of the 25 cases, all four cases of lymphoma showed abnormal lymphocytes with the slit skin smear. Slit skin smear technique appears to be a useful screening test for malignant cells in cutaneous T cell lymphoma and may indicate other specific skin infiltrates. The main advantage of slit skin smear examination resides in its potential for rapid bedside diagnosis of cutaneous T-cell lymphoma. Because the number of cases in our study was limited, evaluation of a larger group of patients is needed to substantiate this observation.

References

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