Practical Aspects Regarding the Histopathological Diagnosis of Early Mycosis Fungoides

Abstract

Mycosis fungoides is the most common primary T-cell lymphoma of skin. The disease has a protean clinical and histological presentation in its early patch and plaque stages, when distinction from mimicking inflammatory dermatoses is difficult. Since no single criterion is specific enough, a reliable diagnosis in early stages requires integration of clinical, histopathological and molecular findings. In skin biopsies, the most helpful histologic features are the detection of atypical lymphocytes in the epidermis with minimal epidermal changes, basal alignment of lymphocytes along dermal-epidermal junction and formation of Pautrier microabscesses. An aberrant immunophenotype of T cells and molecular detection of a clonal T-cell population are factors that could allow a more specific diagnosis. This work recapitulates and discusses these features from a practical perspective.

Dendritic cell distribution in mycosis fungoides vs. inflammatory dermatosis and other T-cell skin lymphoma

“…Our team previously presented studies concerning DC distribution in cutaneous melanoma (1) as well as in mycosis fungoides vs. inflammatory dermatoses (9,10). This preoccupation for DCs revealed interesting results that prompted the initiation of this study.…”

Mycosis fungoides with spongiosis: A potential diagnostic pitfall

“…Massone et al noted marked spongiosis in 3% (28/745) of biopsy specimens in patients with early MF . Diagnostic criteria for MF also include a lichenoid lymphoid infiltrate, atypical lymphoid cells, basal alignment of lymphoid cells along several contiguous rete ridges on the epidermal side of the dermal‐epidermal junction in close apposition to basal kerationcytes,cytological atypia with convoluted or cerebriform hyperchromatic nuclei, epidermotropism defined as individual lymphocytes migrating among epidermal keratinocytes, Pautrier microabscesses (clusters of atypical T‐cells around Langerhans cells), and papillary dermal fibrosis . However, the presence of spongiosis is not part of the diagnostic criteria for MF despite observations to the contrary.…”

Mycosis fungoides: Review and updates

“…The histopathologic picture of patch stage MF is characterized by patchy lichenoid or band-like infiltrates of small to medium sized lymphoid cells in the papillary and superficial reticular dermis, mixed with numerous reactive, non-neoplastic lymphocytes and histiocytes, may be distributed a perivascular and interstitial in addition to the band-like manner. It is associated with slight fibrous thickening of the papillary dermis [73,74] . Papillary dermal fibrosis is one of the key features in the diagnosis of early MF that may lead to a "wiry" collagen appearance [73,75] .…”

“…It is most prevalent in the patch stage and declined with progression of stage to plaque and tumor stage. Epidermotropism has various morphological aspects including: single intraepidermal cells with no tendency to coalesce, linearly arranged single cells along the basal epidermal layer, pagetoid spread of lymphocytes into the epidermis, tiny collections of three to four lymphocytes, and large intraepidermal clusters of atypical lymphoid cells referred to as Pautrier microabscesses [2,73,74] . Basal alignment of lymphocytes along the basal layer of the epidermis has high sensitivity in MF diagnosis and combination of Pautrier's microabscesses and basal lymphocytes correlated significantly with a higher likelihood of MF [73] .…”

“…Epidermis in MF patients shows slight hyperkeratosis, usually in the form of elongated mounds of parakeratosis or scale and crusts. Mild to moderate epidermal thickness increases and psoriasiform hyperplasia are seen (42,74) . However, Hyperplastic epidermal changes, including prominent acanthosis and hyperkeratosis, are not typical for MF and should make one consider the possibility of another diagnosis, such as psoriasis vulgaris for example [73,74] .…”