Laboratory Data

Although this looks like vitiligo or lichen sclerosis et atrophicus, the presence of prominent epidermotropism by large atypical lymphocytes makes mycosis fungoides likely.

Hypopigmented mycosis fungoides is a slow progressive cutaneous T cell lymphoma. It is a rare clinical variant of the disease. Described exclusively in dark skinned or asian patients, it was first described by Ryan in 1973. There are now about 106 reported cases of hypopigmented MF

Hypopigmented MF was more likely to occur in younger patients. Persistent or unusual hypopigmented lesions should be subjected to biopsy to avoid delay in the diagnosis of MF, especially in children. It has a long latent period.

Generally, It has a good response to therapy to PUVA, UVB or topical mechloramine therapy. However, recurrences are common. They have a biologically benign course.

References:

Akaraphanth R, Douglass MC, Lim HW Hypopigmented mycosis fungoides: Treatment and a 6½-year follow-up of 9 patients J Am Acad Dermatol 2000;42:33-9

Ardigó M, Borroni G, Muscardin L, Kerl H, Cerroni L Hypopigmented mycosis fungoides in Caucasian patients: A clinicopathologic study of 7 cases J Am Acad Dermatol 2003;49:264-70

Comments from Members

Choon, Siew Eng FRCP, Department of Dermatology, Hospital Sultanah Aminah, Johor Bahru, Malaysia on Mar 4, 2004

I saw a 29-year-old Afro-Carribean man with hypopigmented MF and have the pleasure of reading the HPE slides personally. I think these 4 articles may be of interest to you, two case reports in caucasians. Sitting in the Dermatopathology Lab in St John's, London makes me wonder how many British are walking about with MF (definitely more than estimated incidence of 4/100000/year incidence) cos' we see so many MF slides per week but so far only one hypopigment MF.

Ref:

1. Landro et al: Pediatric Dermatol, Vol 14(6) Nov/Dec 1997 449-452
2. Neuhaus: Pediatric Derrmatol, Vol 17(5) Sept/Oct 2000 403-406
3. Robert: Br J dermatol Vol 139(2) Aug 1998 341-343
   

Khalifa Shaquie MD, PhD, Professor of Dermatology, College of Medicine, University of Baghdad, Baghdad, Iraq on Nov 12, 2004

In Iraq it is common to see the depigmentation of vitiligo to pass through 2 stages. Stage I vitiligo appears as a whitish-brown patches in colour before changing to stage II vitiligo (milky-white in color). Histopathologically Stage I vitiligo shows epidermal lymphocytic inflammatory reaction with tendency to form Pautrier microabscesses in some instances. The dermis also shows mild to moderate lymphocytic inflammatory reaction in the majority of cases. Hypopigmented MF is a newly described entity appears to share many features with stage I vitiligo; characterised by childhood onset of dark skin people with nonprogressive hypopigmented macules and good response to PUVA therapy. In conclusion we think that many cases which were diagnosed and treated as such are really a stage I hypopigmented vitiligo. Full review article regarding this controversy will be published in future. Regarding the present case we strongly think it is a clinically and histopathologically a case of stage I vitiligo rather than hypopigmented MF.

References
1.Sharquie KE.Stages of depigmentation in vitiligo. Iraqi Med.J 1988;36:47-50.

2.Sharquie KE. The histology and immunopathology of vitiligo. PhD thesis. University of Sheffield, England 1982.

3.Sharquie KE, Mehenna SH,Al-Azzawi H and Naji A. Inflammatory changes in vitiligo(stage I and II depigmentation).Am J Dermatopathology. Vol.26(2) April 2004 pp 108-112.

Salai Jayakumar MD, Professor, Department of Dermatology, Madras Medical College, Chennai, India on January 13, 2007

We are seeing many cases of Hansen's Disease and I think we have to include hypopigmented mycosis fungoides in differential diagnosis. The dermatologist from Baghdad's comment about early vitiligo is quite interesting.

John Andrew Carlson MD, Professor, Divisions of Dermatology and Dermatopathology, Albany Medical College, Albany, NY. USA on January 25, 2007

I believe this case most likely represents hypopigmented MF and not vitiligo.

While it’s true that vitiligo can mimic hypopigmented mycosis fungoides, it’s not typical of vitiligo to show scale, histologically, as seen in this case. In addition, lymphocytes are few in vitiligo- present around superficial venules and sparsely scattered in the lower half of the epidermis associated with slight spongiosis. In this case, numerous lymphocytes are found in the epidermis associated with obvious spongiosis; findings that favor MF over vitiligo.

Not considered in the discussion of this case is the possibility of pityriasis alba. Based on the histology, pityriasis alba is more likely than vitiligo.

Analysis of melanocyte number, melanization of the epidermis and immunophenotyping of the infiltrate could help differentiate between these possibilties. Also, after 2+ years, has this eruption progressed or remained stable despite therapy?

References [1-3]:
[1] Singh ZN, Tretiakova MS, Shea CR, Petronic-Rosic VM. Decreased CD117 expression in hypopigmented mycosis fungoides correlates with hypomelanosis: lessons learned from vitiligo. Mod Pathol. 2006 Sep;19(9):1255-60.
[2] Werner B, Brown S, Ackerman AB. "Hypopigmented mycosis fungoides" is not always mycosis fungoides! Am J Dermatopathol. 2005 Feb;27(1):56-67.
[3] Sharquie KE, Mehenna SH, Naji AA, Al-Azzawi H. Inflammatory changes in vitiligo: stage I and II depigmentation. Am J Dermatopathol. 2004 Apr;26(2):108-12.