The superficial dermis usually contains small keratin-filled cysts; these are a useful clue to the diagnosis but are not specific, as they can also be seen in desmoplastic trichoepithelioma
and other entities.
A desmoplastic trichoepithelioma
is a variant that has stromal sclerosis on pathology.
With microcystic adnexal carcinoma it is difficult to differentiate from infiltrating basal cell carcinoma and desmoplastic trichoepithelioma
. The points which are in favour of microcystic adnexal carcinoma are those being the deep invasion of the tumour into the surrounding tissue stroma, extensive perineural invasion and glandular differentiation (Ductal differentiation).
Patel, "The immunohistochemical differential diagnosis of microcystic adnexal carcinoma, desmoplastic trichoepithelioma
and morpheaform basal cell carcinoma using BerEP4 and stem cell markers," Journal of Cutaneous Pathology, vol.
Hence although formerly thought to be of mixed origin now syringoma is considered to be benign appendage tumour of intra- epidermal eccrine sweat duct.Histopathological differential diagnosis should be fibrosing basal cell carcinoma desmoplastic trichoepithelioma
microcystic adnexal carcinoma.
Eighteen cases of morphoeic basal cell carcinoma and 19 cases of desmoplastic trichoepithelioma
were studied by Costache et al.
It is of limited value in differentiating infiltrative BCC from desmoplastic trichoepithelioma
(DTE), although BCC shows diffuse staining and DTE shows partial staining 16.
(DTE) is a histologic variant of TE that merits additional description.
presents clinically as an enlarging nodule and shows cords and nests of basaloid cells with horn cyst formation, embedded within a sclerotic dermal stroma (Figures 10 and 11) 12].
. Cancer 1977;40:297-9.
Generalized trichoepitheliomas with alopecia and myasthenia gravis: clinicopathologic and immunohistochemical study and comparison with classic and desmoplastic trichoepithelioma
. J Am Acad Dermatol.
Various immunohistochemical markers have been studied to help distinguish desmoplastic trichoepitheliomas
(DTE), infiltrating or morpheaform BCCs, and microcystic adnexal carcinomas, including CD23, CD5, CD10, CD34, CK20, CK15, stromelysin-3, BCL2, AR, pleckstrin homology-like domain, family A, member 1 protein (PHLDA1), p75 neurotrophin receptor (p75NTR), fibroblast activation protein (FAP), Ber-EP4, p63, and others (34-48) (Table 2).