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cysts with follicular germinative differentiation

Wednesday 15 March 2017

Cysts are very common in the routine of dermatopathology but follicular germinative (trichoblastic) differentiation in cysts is seen rarely. The presence of follicular germinative differentiation in a cyst alerts to consider the possibility of a basal cell carcinoma (BCC) arising in a cyst.

Cystic lesions with follicular germinative differentiation have been described in the literature under various names including trichoblastic infundibular cyst, cystic trichoblastoma, cystic panfolliculoma (CPF), dermoid cyst with basaloid proliferations, folliculosebaceous cystic hamartoma and BCC occurring in infundibular cysts.

The lesions could be classified as three cystic trichoblastomas, one CPF and one cystic hamartoma with follicular germinative differentiation.

Histopathologically, cystic trichoblastomas can be separated from CPFs. Some lesions defy classification and may be regarded as cystic follicular hamartomas.

The presence of follicular papillae and bulb-like structures, advanced follicular differentiation like that of inner and outer root sheath exclude the differential diagnosis of BCC arising in a cyst.

Paywall references

- Classification of cysts with follicular germinative differentiation.
López-Takegami JC, Wolter M, Löser C, Maiweg C, Jones M, Metze D, Böer-Auer A.
J Cutan Pathol. 2016 Mar;43(3):191-9. doi : 10.1111/cup.12619
PMID: 26347259