Primary cutaneous adenoid cystic carcinoma: a clinicopathologic, immunohistochemical, and fluorescence in‐situ hybridisation study of 13 cases

Abstract

Aims This study aimed to investigate the clinical, histological, immunohistochemical and chromosomal features of primary cutaneous adenoid cystic carcinoma (PCACC). Methods and results We retrospectively analysed 13 cases identified on their clinicopathological features and performed fluorescence in‐situ hybridisation (FISH) on six available cases. Head and neck (46.2%) were most commonly involved. The median age was 53 years, with a male predilection. Histologically, tumours were classified as grades 1 (eight), 2 (four) and 3 with high‐grade transformation (HGT) (one). The HGT component was demonstrated as poorly differentiated carcinoma with multifocal necrosis and myoepithelial differentiation. Patients with one of the following factors: longest diameter of the lesion (≥ 1 cm), involvement of subcutaneous fat tissue and widely infiltrative border had a relatively higher rate of local recurrence, distant metastasis and death. Five of six cases were confirmed to have MYB translocation, while nuclear staining for MYB proto‐oncogene, transcription factor (MYB) protein was found in four cases. During the follow‐up (median = 64 months), two patients experienced local recurrences. One patient, who was classified as grade III PCACC with HGT, developed multiple metastases and died of disease. Another patient was alive with multiple metastases. Conclusions This is the largest single‐institution study, to our knowledge, of PCACC in an Asian population. We describe the first case of scalp PCACC with HGT, which is the only death case in our series. PCACC tends to recur locally and has metastatic potential. PCACC with HGT has a poor prognosis.

Spiradenoma With Adenoid Cystic Carcinoma–like Changes

“…The myoepithelial cell layer is positive for p63, smooth muscle actin, and S100 around the periphery of the cellular aggregates 31 . Approximately 60% of PCACCs harbor MYB gene activations, either through MYB chromosomal abnormalities or MYB proto-oncogene, transcription factor/nuclear factor I/B ( MYB::NFIB ) fusion 32,33 . Histomorphologically, PACC is indistinguishable from ACC of other anatomic sites, and in some cases, metastasis should be excluded clinically.…”

“…One of our cases, the MYB BA test was positive; however, the sample was nonanalyzable for presence MYB-NFIB fusion. Approximately 70% of ACC (including cases of PCACC) can harbor MYB gene activations, either through MYB chromosomal abnormalities or by the generation of the MYB::NFIB fusion 33,35–38 . Expression of MYB protein in ACC appears to lack a strong correlation with the translocation of the MYB gene, and some studies have demonstrated that immunohistochemical expression of MYB can be seen in ACC without rearrangement of the MYB gene and absence of expression has been observed in cases of ACC showing the rearrangement 36 …”

“…31 Approximately 60% of PCACCs harbor MYB gene activations, either through MYB chromosomal abnormalities or MYB proto-oncogene, transcription factor/nuclear factor I/B (MYB::NFIB) fusion. 32,33 Histomorphologically, PACC is indistinguishable from ACC of other anatomic sites, and in some cases, metastasis should be excluded clinically. The differential diagnosis of PCACC includes an adenoid-cystic variant of basal cell carcinoma, primary cutaneous cribriform carcinoma, and primary mucinous carcinoma.…”

“…Approximately 70% of ACC (including cases of PCACC) can harbor MYB gene activations, either through MYB chromosomal abnormalities or by the generation of the MYB::NFIB fusion. 33,[35][36][37][38] Expression of MYB protein in ACC appears to lack a strong correlation with the translocation of the MYB gene, and some studies have demonstrated that immunohistochemical expression of MYB can be seen in ACC without rearrangement of the MYB gene and absence of expression has been observed in cases of ACC showing the rearrangement. 36 To the best of our knowledge, this is the largest series in the English literature of spiradenoma with ACC-like features.…”

Recent Advances on Immunohistochemistry and Molecular Biology for the Diagnosis of Adnexal Sweat Gland Tumors

“…Molecular biology: Fusions of MYB or MYBL1 with NFIB are detected in 40-97% of adenoid cystic carcinomas with very high specificity [5,6,12,16,19,20]. The most frequent fusions are MYB::NFIB fusion (73-83%) and MYBL1::NFIB (20-23%) [16,[21][22][23][24], with detection of gene rearrangement in both myoepithelial and ductal epithelial cells [22]. Up to 83% of cutaneous cases demonstrate MYB rearrangement.…”