Histopathologic Evaluation of Parapsoriasis from the Perspective of NB-UVB/PUVA Therapy on the Outcome and Recurrence of the Disease.

Sir,

Parapsoriasis, presented as an early stage of cutaneous T-cell lymphoma, is mostly treated with psoralen and ultraviolet A (PUVA) therapy and narrowband ultraviolet B (NB-UVB) phototherapy.[12] In the present study, our aim was to document the histopathologic findings before and after NB-UVB/PUVA treatment and to compare these findings with the existence of disease recurrence and clinical subtypes.

The archived files of small plaque parapsoriasis (SPP) and large plaque parapsoriasis (LPP) patients with control biopsies taken between 2008–2017 at the dermatology clinic in Mustafa Kemal University, were reviewed and 53 patients were selected. Biopsies of these patients treated with NB-UVB/PUVA were evaluated histopathologically before and after treatment. The architecture of the epidermis, the presence of epidermotropism and interface dermatitis, the type of dermal infiltrate and its distributions, were examined. The histopathologic parameters were evaluated semiquantitatively.[34] Around 37 patients had been available for recurrence data collection through clinical follow-up, and the rest were off the record. The statistical analyses were performed using Pearson's Chi-square, Wilcoxon signed-rank, and Mann Whitney-U tests.

There were 40 (75.5%) SPP and 13 (24.5%) LPP patients [Figures 1 and 2]. The patients' mean age was 50.91 ± 13.33. Of the 53 patients, 38 (71.6%) were male and 15 (28.4%) were female. While 16 (30.2%) patients had recurrence, 37 (69.8%) patients remained disease-free. Epidermotropism was found in all cases and single lymphocyte epidermotropism was the most prominent finding before treatment (45%) [Figure 3]. Epidermal changes seemed to be the most common finding before treatment. While 10 (18.9%) cases had no epidermal damage, 20 (37.7%) cases presented with psoriasiform hyperplasia and 23 (40.5%) cases had irregular hyperplasia. Moreover, parakeratosis was observed in 17 (32.1%) cases and epidermal findings were diminished in 40 (75.5%) cases after treatment. There were dermal changes in all cases after treatment [Figure 4], fibrosis and melanophage infiltration were statistically significant (P < 0.001 in both). The distribution of histopathologic parameters before and after treatment was statistically similar among patient biopsies with and without recurrence including clinical subtypes (P > 0.05) [Table 1].

Figure 1

Small plaque parapsoriasis lesion in a patient

Figure 2

Large plaque parapsoriasis represented clinically

Figure 3

Single/haloed atypical lymphocytes in epidermis with superficial dermal infiltration before treatment (× 20, H&E)

Figure 4

Vacuolar degeneration in basal layer of epidermis, melanophages and increased collagen bundles in papillary dermis (× 20, H&E)

Table 1

Morphologic characteristics of parapsoriasis patients before and after phototherapy

Feature/Intensity	Absent (No) Before/After	Mild (No) Before/After	Moderate (No) Before/After	Severe (No) Before/After	P Before/After
Epidermis
Normal Epidermis	10/13	-	-	-	0.4
Psoriasiform hyperplasia	20/52	4/0	11/1	5/0	0.0
Irregular hyperplasia	31/49	9/4	12/0	1/0	0.0
Flat and/or atrophic epidermis	52/20	0/17	1/11	0/5	0.0
Spongiosis	53/53	0/0	0/0	0/0	1
Necrotic keratinocytes	52/53	1/0	0/0	0/0	0.31
Parakeratosis	36/53	7/0	9/0	1/0	0.0
Changes at the dermoepidermal junction
Focal interface dermatitis	35/53	7/0	11/0	0/0	0.0
Widespread interface dermatitis	42/53	3/0	7/0	1/0	0.02
Epidermotropism
Single lymphocyte epidermotropism	25/51	15/2	9/0	0/0	0.0
Basilar lymphocytes	42/53	1/0	9/0	1/0	0.002
Pautrier’s microabscesses	38/52	12/1	3/0	0/0	0.00
Haloed lymphocytes	52/52	1/1	0/0	0/0	0.31
Disproportion exocytosis	46/52	2/1	5/0	0/0	0.02
Pagetoid epidermotropism	51/52	0/0	2/1	0/0	0.01
Absence of epidermotropism	52/1	0	0	0	0.30
Atypical lymphocytes
Only in the epidermis	53/53	0/0	0/0	0/0	1
Both in epidermis and dermis	42/53	4/0	7/0	0/0	0.002
Only in the dermis	46/53	3/0	4/0	0/0	0.015
Dermal lymphocytic infiltrate
Band-like	48/53	0/0	4/0	1/0	0.034
Patchy-lichenoid	45/53	2/0	5/0	1/0	001
Superficial-perivascular	15/40	6/12	29/1	3/0	0.00
Periadnexal	50/53	3/0	0/0	0/0	0.008
Eosinophils	53/53	0/0	0/0	0/0	1.0
Dermal changes
Papillary dermal fibrosis	52/6	1/23	0/19	0/5	0.00
Melanophages	51/9	1/40	1/4	0/0	0.00
Purpura	52/53	1/0	0/0	0/0	0.31
Edema of the papillary dermis	50/51	2/2	1/0	0/0	0.48

In conclusion, single lymphocyte epidermotropism was the most prominent finding before treatment, lack of epidermal and dermal lymphocytic inflammation should be emphasized as successful parameters of NB-UVB/PUVA treatment including dermal fibrosis and melanophages [Figure 4], the histopathologic findings before and after treatment were similar between the SPP and LPP groups, and the histopathologic findings before and after treatment were similar among cases with and without recurrence.

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Conflicts of interest

There are no conflicts of interest.