Histopathologic findings in the clinically uninvolved skin of patients with mycosis fungoides

An Asymptomatic Case of Invisible Mycosis Fungoides

ABSTRACT

Mycosis fungoides has previously been reported in 'invisible' form, when biopsy of normal-appearing skin in the background of undifferentiated chronic pruritus demonstrated histopathologic findings of the malignancy. Asymptomatic cases have been reported more infrequently on biopsies of individual skin lesions. We present a case of invisible and asymptomatic mycosis fungoides, confirmed with immunohistochemical and T-cell receptor gene rearrangement studies, diagnosed on a re-excision specimen of an atypical melanocytic nevus. The case highlights the importance of alert examination of all tissue specimens for evidence of unrelated pathologic findings.

Real-life experience with chlormethine gel for early-stage mycosis fungoides with emphasis on types and management of cutaneous side-effects. J DERMATOL TREAT 2021;33:2364-2370. [PMID: 34427536 DOI: 10.1080/09546634.2021.1967266]

BACKGROUND

Real-life efficacy data on the recently approved once daily application of chlormethine gel (CG) for mycosis fungoides (MF) is limited, and detailed characterization of the side effects and their management are strikingly sparse.

OBJECTIVE

To evaluate the efficacy and particularly the side effect profile of CG in early-stage MF patients in a real-life setting.

METHODS

We performed a single-center retrospective analysis of 66 early-stage MF adult patients treated with CG in 2016-2019.

RESULTS

Treatment with a once-daily application (52%), or at lower frequencies (48%), in some with topical corticosteroids (TCS) (40%), resulted in an overall response rate of 50%, with no significant difference between stage IA and IB. Cutaneous side effects (56%) included irritant or allergic contact dermatitis (36%, mostly mild/moderate and manageable by reducing application frequency and/or adding TCS or interrupting treatment), unmasking effect (9%), hyperpigmentation (14%), and pruritus (9%). Withdrawal due to side effects occurred in 19.6% of patients (15% for contact dermatitis).

CONCLUSION

In real-life management, flexible regimens of CG sometimes with TCS, show efficacy in early-stage MF and may reduce the rate of contact dermatitis, the main treatment-limiting side effect. Practical recommendations with emphasis of the types, time of appearance, and management of side effects are provided.

Mycosis fungoides and Sézary syndrome: clinical, histopathological and immunohistochemical review and update

This paper reviews the diagnostic and classificatory concepts of mycosis fungoides and Sézary syndrome in light of the latest normative publications. It describes the great variability of the clinical expression of mycosis fungoides in its early stages as well as the histopathological and immunohistochemical aspects that help with diagnosis. The diagnostic criteria required for characterizing Sézary syndrome and the staging system used for both mycosis fungoides and Sézary syndrome are described.

Idiopathic guttate hypomelanosis-like lesions in patients with mycosis fungoides: a new adverse effect of phototherapy

BACKGROUND

Idiopathic guttate hypomelanosis (IGH) is a common pigmentary disorder, the aetiology and pathogenesis of which are largely unknown. The appearance of IGH-like lesions during phototherapy has been reported previously in only one patient.

OBJECTIVE

To describe the clinical and histological features of phototherapy-induced IGH-like lesions, their relation to ultraviolet dosimetry and the course of this eruption in patients with mycosis fungoides (MF).

METHODS

The files of all patients with MF who underwent phototherapy in our centre from 1992 to 2008 were searched to identify those in whom IGH-like lesions appeared during treatment. Results Among 87 patients with early-stage MF who underwent phototherapy, seven acquired IGH-like lesions during monotherapy with narrow-band ultraviolet B (NB-UVB; four patients) or psoralen and ultraviolet A (PUVA; three patients). All but one had a light complexion. The lesions appeared in areas exposed to ultraviolet light, and not exclusively on the skin previously involved by the disease. The mean number of exposures until appearance of the lesions was 92 for NB-UVB and 137 for PUVA. Biopsy study showed a decreased number of melanocytes. Phototherapy was discontinued in four patients, of whom three showed a partial or complete disappearance of the IGH-lesions. The other three patients are still receiving phototherapy, with no change in their IGH-like lesions.

CONCLUSIONS

Phototherapy may induce an eruption bearing similar clinical and histopathological features to IGH. The eruption is rare, appears to emerge only after prolonged therapy and seems to be reversible upon discontinuation of phototherapy. IGH-like eruption should be added to the list of side-effects of phototherapy.

Microscopic study of normal skin in cases of mycosis fungoides

BACKGROUND

During therapy of patients with mycosis fungoides (MF) at the Department of Dermatology, Kasr El-Aini Hospital, follow-up biopsies are routinely taken every 2 months. It was noticed that lesions of MF might become clinically normal during treatment, and yet still show microscopical evidence of MF. This finding raised the possibility that clinically normal skin in MF could be microscopically involved.

AIM

The aim of our work was to evaluate the degree of histopathological involvement of normal-looking skin in patients with MF.

PATIENTS AND METHODS

Thirty patients with stage IB were biopsied from their normal skin. Two biopsies were taken: one proximal (2 cm) and the other distal (> 5 cm) from any visible lesion. Ten normal controls were included in the study. All specimens were stained with H&E and examined microscopically. The microscopical diagnosis was confirmed by immunophenotyping.

RESULTS

Epidermotropism was detected in 21 (70%) of the proximal skin biopsies and 14 (47%) of the distal skin biopsies, whereas no biopsy from the control group showed epidermotropism. All the proximal skin biopsies showed dermal infiltrate and 90% of the biopsies from the distal normal skin showed dermal infiltrate (mostly superficial perivascular).

CONCLUSION

Normal skin in patients with MF could be affected microscopically and this may raise questions regarding the credibility of the current staging classification of MF, and may necessitate taking biopsies from normal skin before starting topical treatment. During MF treatment, biopsies from cured lesions are required before starting withdrawal.

Invisible mycosis fungoides: a diagnostic challenge

We describe a 76-year-old woman who had persistent generalized pruritus as the only cutaneous manifestation of a cutaneous T-cell lymphoma (mycosis fungoides). No cutaneous lesions were observed throughout the patient's course. Skin biopsy specimens obtained from normal-looking pruritic skin revealed a discrete perivascular lymphocytic infiltrate in the upper dermis and focal intraepidermal clusters of atypical lymphoid cells (Pautrier's microabscesses). PCR analysis of TCR-gamma gene disclosed a monoclonal T-cell rearrangement. Sequencing of the PCR monoclonal product identified the J(8)V(2)C(2) TCR gene rearrangement. This observation illustrates the existence of a peculiar and exceedingly rare form of mycosis fungoides characterized only by persistent pruritus unresponsive to several therapeutic approaches. The diagnostic difficulties of this rare variant are stressed.

Invisible mycosis fungoides: A diagnostic challenge

We describe a 76-year-old woman who presented persistent generalized pruritus as the only cutaneous manifestation of a cutaneous T-cell lymphoma (mycosis fungoides). No cutaneous lesions were observed throughout the patient's course. Skin biopsies obtained from normal-looking pruritic skin revealed a discrete perivascular lymphocytic infiltrate in the upper dermis and focal intraepidermal clusters of atypical lymphoid cells (Pautrier's microabscesses). PCR analysis of TCR-gamma gene disclosed a monoclonal T-cell rearrangement. Sequencing of the PCR monoclonal product identified the J(8)V(2)C(2) TCR gene rearrangement. This observation illustrates the existence of a peculiar and exceedingly rare form of mycosis fungoides characterized only by persistent pruritus unresponsive to several therapeutic approaches. The diagnostic difficulties of this rare variant are stressed.

Cutaneous T-cell lymphoma. Refinement in the application of controversial histologic criteria

The term cutaneous T-cell lymphoma was originally coined to encompass the spectrum of mycosis fungoides and Sézary syndrome. It has become increasingly evident that the histopathologic diagnosis of CTCL can be exceedingly challenging. A series of recent studies, however, have helped clarify the nature of the histologic findings in CTCL. Recently reported histologic data on mycosis fungoides, Sézary syndrome, and their variants is emphasized in this article, with special focus given to the findings in early lesions. A brief summary of lymphocyte immunophenotyping and the role of T-cell reception gene rearrangements in CTCL is included.

Management of cutaneous lymphoma

The foregoing underlines the advances which have been made in our understanding of cutaneous lymphoma and the areas where further research is needed. With a few noteable exceptions the aim of therapy in CTCL is palliative rather than curative and treatment success is measured in terms of disease-free interval. There is still no evidence that any chemotherapeutic regimen prolongs survival. A possible exception is the effect of photopheresis in Sézary syndrome but our own experience differs from that in the USA and underlines the need to identify patients with clonal disease when defining subjects for study. The combination of genotypic analysis and new treatment methods offers exciting new prospects in the management of patients with cutaneous lymphoma.