Clinicopathologic Variants of Mycosis Fungoides

Unilesional mycosis fungoides: a case report and review of literature

Mycosis fungoides (MF) is the commonest primary cutaneous T-cell lymphoma (CTCL). Classically MF is presented clinically as multilesional disease but occurrence of solitary lesion, though quite rare, is on the record. This rare variant of MF is clinically and histopathologically indistinguishable from classic MF. Due to the rarity of the presentation the clinician may miss the diagnosis and the pathologist may also be in diagnostic dilemma specially if not clinically oriented. Here we describe a case of unilesional/solitary MF (UMF) in a 59 years old male who was initially clinically diagnosed as inflammatory dermatosis and was treated accordingly without any appreciable clinical response for over 4 years. Unresponsiveness to empirical treatment led to biopsy which finally proved it to be UMF. The clinical, light microscopic and immunohistochemical features of UMF are briefly reviewed to create awareness among the clinicians and pathologists about this rare variant of MF. IMC J Med Sci 2022; 16(1): 006 *Correspondence: Wasim Selimul Haque, Head, Department of Histopathology and Cytopathology, Jaber Al-Ahmed Armed Forces Hospital, Kuwait Armed, Forces, Subhan Cantonment, Kuwait. Email: audrirodelawasim@gmail.com

Mycosis fungoides in a patient with ulcerative colitis on anti-tumor necrosis factor-alpha therapy

A 46-year-old man with a history of ulcerative colitis (UC) for over 25 years was treated with infliximab for 7 years. He noticed gradually spreading erythema on his right lower abdomen, femur, and buttocks. Skin biopsy from the right lower abdomen revealed massive invasion of lymphocytes in the papillary dermis and epidermal layer. In conjunction with the findings of immunohistochemistry, the skin lesion was diagnosed as mycosis fungoides (MF) at infiltration stage. Infliximab was discontinued, and narrow-band ultraviolet light B therapy was initiated to treat the skin lesion. The patient achieved remission for MF following treatment and UC has not relapsed for more than 1 year with 5-aminosalicylic acid treatment alone. This is the first case of MF in a UC patient treated with anti-tumor necrosis factor-alpha (anti-TNFα). Lymphoma occurrence is a complication of treatment with anti-TNFα agent or thiopurine. However, there is no evidence regarding the relationship between MF and UC. Hence, these immunomodulatory agents may have triggered the occurrence of MF in this case. When treating UC patients with immunomodulatory agents, the possibility of MF or other types of lymphoma as rare complications must be considered.

Thymocyte selection-associated high-mobility group box as a potential diagnostic marker differentiating hypopigmented mycosis fungoides from early vitiligo: A pilot study

BACKGROUND

Hypopigmented mycosis fungoides is a rare variant of mycosis fungoides that may mimic many benign inflammatory hypopigmented dermatoses, and as yet there is no identified marker to differentiate between them.

AIM

The aim of this study was to study the expression of thymocyte selection-associated high-mobility group box (TOX) in hypopigmented mycosis fungoides and one of its inflammatory mimickers (early active vitiligo) to assess its potential as a differentiating diagnostic marker.

METHODS

A case-control study was done using immunohistochemical analysis of TOX expression in 15 patients with hypopigmented mycosis fungoides and 15 patients with early active vitiligo. Immunohistochemical analysis was done via a semi-quantitative method and an image analysis method.

RESULTS

Hypopigmented mycosis fungoides showed a statistically significant higher expression of TOX than early active vitiligo. The expression of TOX was positive in a majority of hypopigmented mycosis fungoides cases (14 cases, 93.3%), while only one case (6.7%) of vitiligo was weakly positive. TOX also displayed 93.3% sensitivity and specificity, with a cut-off value of 1.5.

LIMITATIONS

This was a pilot study testing hypopigmented mycosis fungoides against only a single benign inflammatory mimicker (early vitiligo). Other benign mimickers were not included.

CONCLUSION

Our findings showed that TOX expression can differentiate hypopigmented mycosis fungoides from early active vitiligo which is one of its benign inflammatory mimickers, with a high degree of sensitivity and specificity.