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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.