A Histological Snapshot of Hypothetical Multistep Progression From Nevus Sebaceus to Invasive Syringocystadenocarcinoma Papilliferum

Abstract

Syringocystadenocarcinoma papilliferum (SCACP) is an extremely rare adnexal neoplasm, believed to arise in a preexisting nevus sebaceus of Jadassohn (NSJ) through a multistep progression process. This hypothetical process involves an NSJ giving rise to syringocystadenoma papilliferum, which then presumably undergoes malignant transformation in rare circumstances to give rise to SCACP in situ, which finally progresses to an invasive SCACP. Of the 30 SCACP cases reported so far, none have documented the process from a birthmark to the final invasive lesion, with histological evidence of each step, in a single tumor. Here, the authors report just such a case. A 74-year-old man presented with a recently enlarging birthmark on the scalp. Excisional biopsy showed an invasive SCACP, in the background of SCACP in situ, syringocystadenoma papilliferum, and NSJ. Furthermore, this tumor showed a concurrent pigmented trichoblastoma and histological evidence of lymphovascular invasion, events that have not been documented with SCACP. Interestingly, all these component lesions were present on a single histological section of this solitary tumor. Regional lymph node metastasis, a rare occurrence in SCACP, was also present in this remarkable case. The authors discuss the implications of these findings in light of the review of relevant literature.

Syringocystadenocarcinoma papilliferum: Clinicopathologic analysis of 10 cases

“…SCACP is thought to be a low‐grade malignancy with a favorable prognosis . Among the 38 cases reported, locoregional lymphatic metastases were found in only 7 (18.4%) patients to date, with none of them having any distant metastases . In 1949, there was 1 case described as sweat gland carcinoma, which was probably SCACP that metastasized to pleura, liver, peritoneum and regional lymph nodes and the patient died owing to disseminated disease .…”

“…Syringocystadenocarcinoma papilliferum (SCACP) is an exceedingly rare cutaneous adnexal neoplasm, which is listed in the World Health Organization (WHO) classification of skin tumors as the malignant counterpart of syringocystadenoma papilliferum (SCAP). Since the first description in 1980 by Dissanayake and Salm, less than 40 cases have been reported in the literatures till date . Most of them have been published as case reports, with the only large series of 6 cases described by Kazakov et al Most tumors seem to develop over a pre‐existing SCAP, and some were reported to be associated with nevus sebaceus .…”

An 8‐year‐old girl with a papule on her cheek

“…Histopathologically, there is invagination of the overlying epidermis forming cystic spaces that are lined by double‐layered glandular epithelium overlying central papillary projections of various size, shape, and number made of fibrovascular cores with a lymphoplasmacytic infiltration . The glandular epithelium is made of cuboidal to columnar epithelial cells that may display decapitation secretion and hyperplasia . The glands are in direct communication with the epithelium, allowing the glandular products to be secreted from the lesion, which probably contributed to the patient's experience of bleeding…”

“…It was discovered that NSJ is a mosaic RASopathy with postzygotic mosaic mutations in the HRAS and KRAS genes . The resultant constitutive activation of the MAPK and PI3K‐Akt signaling pathways may predispose certain individuals to develop secondary tumors in NSJ such as SCAP …”

Syringocystadenoma Papilliferum: A Case Report and Review of the Literature

“…However, slowly growing fleshy plaque that has been growing for years and sometimes oozes fluid and sometimes bleeds is characteristic for SP. Syringocystadenocarcinoma papilliferum, which is the malignant counterpart of SP, should be ruled out when evaluating the histopathology of SP [4]. Basal cell carcinoma has been reported to be seen in 10% of patients with SP.…”