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SHORT COMMUNICATION ActaDV ActaDV
Advances in dermatology and venereology Acta Dermato-Venereologica
Locally Aggressive Trichoblastic Tumours ( Low-grade Trichoblastic Carcinomas ): Clinicopathological Analysis and Follow-up
Camille HUA 1 – 3 # , Charles VELTER 3 , 4 # , Amelie OSIO 1 – 3 , Céleste LEBBÉ 5 – 7 , Nicole BASSET-SEGUIN 5 – 7 , Bernard CRIBIER 4 # and Maxime BATTISTELLA 1 – 3 # *
1
Inserm , U 1165 , 2 Université Paris Diderot , Sorbonne Paris Cité , Laboratoire de Pathologie , UMR-S 1165 , 3 Pathology Department , Hôpital Saint Louis APHP , 1 avenue Claude Vellefaux , FR-75010 Paris , 4 Clinique Dermatologique , Université de Strasbourg , Hôpitaux universitaires de Strasbourg , Strasbourg , 5 APHP , Hôpital Saint-Louis , Department of Dermatology , 6 Université Paris Diderot , Sorbonne Paris Cité , and
7
Inserm , U 976 , Paris , France . * E-mail : maxime . battistella @ aphp . fr
#
These authors contributed equally . Accepted Apr 18 , 2017 ; Epub ahead of print Apr 19 , 2017
Trichoblastoma is a predominantly dermal benign hair follicle tumour , characterized by well-circumscribed nests and cords of bland follicular basaloid cells in close association with stroma ( 1 ). Some cases of trichoblastic tumours with regular cytology contrasting with locally invasive growth have been reported with a wide variety of terms , such as “ low-grade trichoblastic carcinomas ” ( 2 , 3 ), “ unusually aggressive trichoblastoma ” ( 4 ) or “ plaque variant of trichoblastic fibromas ”( 5 ). All these cases appear similar , characterized by a large tumour size and poorly circumscribed subcutaneous and sometimes muscular infiltration . This type of locally aggressive trichoblastic tumours do not seem to recur if excised completely , but long-term follow-up is not well established ( 6 , 7 ). In this work , we aimed to examine the clinicopathological features and follow-up data of locally aggressive and cytologically regular trichoblastic tumours , and to determine their malignant potential .
METHODS
The archives of the Departments of Dermatopathology at Strasbourg Hospital and Paris Saint-Louis Hospital were searched for all cases of trichoblastic tumours with benign cytology ( regular small nucleus , evenly distributed chromatin , small nucleolus , and regular nuclear membrane ), infiltrative growth pattern and invasion of subcutaneous tissue or underlying structures , diagnosed between 1997 and 2014 . Basaloid-cell tumours with cytological atypia , prominent peripheral palisading or prominent peritumoural retraction artefact were excluded . Among a total of 1,666 trichoblastic tumours diagnosed in the inclusion period , 36 cases met the inclusion criteria .
All formalin-fixed paraffin-embedded surgical specimens were stained with haematoxylin and eosin and reviewed blindly to
Fig . 1 . Locally aggressive trichoblastic tumours on the leg of a woman ( left ) and a man ( right ). follow-up data by 4 investigators with experience in dermatopathology ( CH , CV , BC , MB ). When remaining tumour tissue was available , immunohistochemical staining for PHLDA1 ( clone sc-23866 , Santa Cruz Biotechnology ; dilution 1 / 100 ) was performed on an automated Benchmark Ultra immunostainer ( Ventana / Roche , Basel , Switzerland ). Clinical data recorded included sex and age at the time of diagnosis , tumour location , tumour size , type of treatment , number of excisions to reach complete resection , tumour recurrence , and follow-up time . The main histopathological data recorded included presence of mitotic activity , presence of apoptosis , presence of tumour necrosis , depth of the tumour infiltration ( subcutaneous tissue , muscular ), connection to the epidermis , ulceration , and features of the stromal component .
RESULTS Clinical findings
Data for 36 patients were analysed . The clinicopathological features of the present study population are summarized in Table SI 1 . The median age at diagnosis was 64 years ( range 39 – 98 years ), with male predominance ( 63.9 %). Involved sites were most often the face ( 60 %) followed by the trunk ( 20 %) and the limbs ( 17.1 %) ( Fig . 1 ). The tumours had a median diameter of 23 mm ( range 15 – 50 mm ), and most often presented as smooth nodules . The 6 tumours with focal microscopic ulceration were not different in terms of size or location distribution , and large clinical ulceration was never present . First intention treatment consisted of surgical excision with 5 – 10-mm margins from the clinical tumour borders in all 36 cases . After the first excision , free margins were obtained in 5 cases , deep margin was involved in 26 ( 72 %) and lateral margin in 19 ( 53 %) cases . One patient with initial deep surgical margin involvement refused complementary surgery and received adjuvant radiotherapy ( total dose 30 Gray ). The median number of surgical excisions required for complete removal was 2 ( range 1 – 5 ), with a median total excision margin of 10 mm . Five tumours required 3 – 5 surgical excisions to obtain free margins ; most of which ( 4 / 5 ) involved the centrofacial area . Follow-up data were available for 20 ( 55.6 %) patients , including 2 whose tumours showed perineural invasion . During a median follow-up of 64.2 months ( range 10 – 120 months )
1 https :// www . medicaljournals . se / acta / content / abstract / 10.2340 / 00015555-2678 doi : 10.2340 / 00015555-2678 Acta Derm Venereol 2018 ; 98 : 126 – 127
This is an open access article under the CC BY-NC license . www . medicaljournals . se / acta Journal Compilation © 2018 Acta Dermato-Venereologica .