A rare combination of sebaceoma with carcinomatous change (sebaceous carcinoma), trichoblastoma, and poroma arising from a nevus sebaceus

Secondary Malignant Tumors Arising in Nevus Sebaceus: Two Case Reports

Nevus sebaceus is a benign tumor that is present at birth and is often seen on the scalp or face. Secondary malignant tumors sometimes occur in nevus sebaceus in adulthood. Herein, we present two malignant tumors arose from nevus sebaceus. One is basal cell carcinoma on the face and the other is sebaceus carcinoma on the lower back, where nevus sebaceus rarely occurs. Basal cell carcinoma sometimes develops in sebaceus nevus after a few decades, seen usually on the scalp or face. Sebaceus carcinoma is a rare malignant tumor that arises in nevus sebaceus.

Development of seven secondary neoplasms in a nevus sebaceous: a case report and literature review

Nevus sebaceous of Jadassohn is a congenital cutaneous hamartoma with epidermal, sebaceous, follicular, and apocrine structures that usually appears at birth or in early childhood. It has the potential to generate a variety of secondary neoplasms of different lineages, and the risk increases with patient age. Although multiple neoplasms may occasionally arise within the same lesion, the coexistence of more than five secondary tumors is extremely rare. Here we report a case of seven secondary tumors including syringocystadenoma papilliferum, desmoplastic trichilemmoma, sebaceoma, trichoblastoma, pigmented trichoblastoma, sebaceous adenoma, and tumor of follicular infundibulum arising within a nevus sebaceous. The complete diagnosis relies on the histopathological analysis of multipoint biopsies and delicate pathological sections.

A Rare Occurrence of Sebaceous Carcinoma, Sebaceoma, Syringocystadenoma Papilliferum, and Trichoblastoma in a Single Nevus Sebaceous Lesion

Nevus sebaceous (NS) is a benign tumor with the potential to develop secondary benign and malignant neoplasms. It is a rare phenomenon to develop 2 or more skin tumors in a single NS lesion. We report a case of multiple secondary tumors, such as sebaceoma, sebaceous carcinoma, syringocystadenoma papilliferum, and trichoblastoma, in a single NS lesion.

Genetic analyses of a secondary poroma and trichoblastoma in a HRAS-mutated sebaceous nevus

A sebaceous nevus is a congenital skin hamartoma caused by postzygotic HRAS or KRAS mosaic mutations. With age, affected individuals may develop secondary tumors within a sebaceous nevus. RAS mutations are harbored from the onset of sebaceous nevus, and further mutations can be expected to be required in order to explain the initiation of secondary tumors. However, genetic analyses of the secondary tumors have not been conducted. Herein, we describe the rare coexistence of a poroma and a trichoblastoma arising in a sebaceous nevus. This is the first report of an investigation of multiple genes in a secondary tumor in an SN. First, HRAS c.37G>C, which is the common mutation in sebaceous nevus, was detected in all three lesions (sebaceous nevus, poroma, and trichoblastoma). Next, to elucidate the potential second-hit mutations in the secondary poroma and trichoblastoma, we applied a panel sequencing for skin cancers that was newly developed in our institution. Our comparison of the mutational profile of 95 skin cancer-related genes in each of the three lesions newly revealed TP53 p.R158P in the poroma and NOTCH2 p.G329S in the trichoblastoma. TP53 p.R158P has been determined as a pathogenic mutation in other tumors, and NOTCH2 p.G329S was a novel mutation. We identified two novel mutations that may have contributed to the pathogenesis of the secondary tumor's development. The roles of the mutations remain unclear.

Eccrine Poroma Arising within Nevus Sebaceous

Secondary neoplasms in nevus sebaceous can develop during adolescence and adulthood. Trichoblastoma and syringocystadenoma papilliferum are the most common benign neoplasms, but poroma is rarely reported. A 28-year-old female presented with an asymptomatic mass on the scalp. She has had a hairless lesion on the scalp since birth. A soft mass developed on that lesion four years prior. Physical examination revealed a localized 1 cm×2.5 cm-sized brownish, verrucous-surfaced plaque with a 1 cm×1 cm-sized pedunculated erythematous tumor on the scalp. We performed skin biopsy on both the plaque and tumor lesions. The histopathological findings demonstrated the plaque lesion consistent with nevus sebaceous and the tumor lesion consistent with eccrine poroma. Surgical mass excision was performed. The patient was eventually diagnosed with eccrine poroma arising within nevus sebaceous. To the best of our knowledge, there are only six reported cases on poroma arising within nevus sebaceous. Although rarely documented in the literature, it should be considered as a secondary neoplasm within nevus sebaceous.

Impact of surgery and adjuvant treatment on the outcome of extraocular sebaceous carcinoma: a systematic review and individual patient's data analysis of 206 cases

BACKGROUND

Extraocular sebaceous carcinoma (EOSC) is an aggressive malignancy of the sebaceous gland. Surgery is considered the cornerstone of treatment, but there is lack of clarity about extent and adjuvant treatment.

METHODS

We conducted a systematic review and analysis of individual patient data of all published cases of EOSC to look into demography, pattern of care, importance of type of surgery, and other adjuvant treatment and survival outcome. A search of PubMed and Google Scholar was done with the key words sebaceous carcinoma, extraocular sebaceous carcinoma, and Muir-Torre syndrome till December 2017. The data were compiled in an Excel chart and analyzed using SPSS IBM software.

RESULTS

Data of 206 patients were retrieved. Median age at presentation was 65 years (range: 11-96 years). Surgery was performed in all except 13 patients. Of these 13, eight were deemed inoperable for extensive disease, and five had metastatic disease. Median PFS and OS for the entire cohort were 84 months (95% CI: 10-158 months) and 92 months (95% CI: 59-126 months). Univariate analysis revealed significantly poor survival for patients with a metastatic disease, regional nodal metastasis, and those with Mohs micrographic or incomplete surgery.

CONCLUSION

EOSC is a disease of elderly patients with good prognosis. Complete surgery with regional lymph node dissection is standard treatment. The role of adjuvant radiotherapy is debatable but can be considered in patients with incomplete surgery or high-risk factors.

Sebaceous Neoplasms

Sebaceous skin tumors are classified into sebaceous adenoma, sebaceoma, and sebaceous carcinoma. An additional group of cystic sebaceous tumors indicate the Muir-Torre syndrome (MTS). Cystic sebaceous tumors are considered as morphologic variants of the 3 main categories. Multilineage adnexal tumors with partly sebaceous differentiation may pose a challenge to categorize. Sebaceous hyperplasia and nevus sebaceus are not considered as true sebaceous tumor entities. Recently, attention has been drawn to morphologic clues of sebaceous differentiation. Immunohistochemistry using the mismatch repair proteins and/or genetic microsatellite instability testing should be performed on sebaceous neoplasms to diagnose MTS as early as possible.

Eccrine Poroma Arising within Nevus Sebaceous

Nevus sebaceous is a congenital, benign hamartomatous lesion, characterized by a yellowish to skin-colored, hairless, verrucous plaque on the head and neck region. In later life, a secondary tumor, either benign or malignant, can develop within nevus sebaceous. Eccrine poroma developing on nevus sebaceous is extremely rare. There are few case reports of eccrine poroma developing within nevus sebaceous. We report a case of a 30-year-old female who presented with a congenital, hairless, verrucous, yellowish lesion on the scalp and an erythematous nodule arising within the yellowish lesion for 8 months. Her clinical presentation and histopathological findings were compatible with nevus sebaceous and eccrine poroma.

Secondary neoplasms arising from nevus sebaceus: A retrospective study of 450 cases in Taiwan

Nevus sebaceus is frequently associated with the development of secondary neoplasms. Incidences of malignant transformation vary among different reports and few data is available regarding Asian populations. We aimed to determine the characteristics of secondary tumors developing from nevus sebaceus in a Taiwanese population and to review the published work. Patients with clinically and histologically confirmed nevus sebaceus were identified from 1992 to 2012 in a medical center. Among the 450 cases of nevus sebaceus, 38 secondary neoplasms were noted, accounting for 8.5% of all cases. Benign tumors represented more than 80% of all tumors. Syringocystadenoma papilliferum (2.7%) was the most common benign tumor, followed by trichoblastoma (1.6%) and trichilemmoma (1.6%) whereas basal cell carcinoma (0.9%) was the most frequent malignant tumor on nevus sebaceus and its clinical features were not typical. All the malignant tumors on nevus sebaceus were noted only in adulthood and the mean age of those with basal cell carcinoma was significantly older than that of trichoblastoma (P = 0.028). Our study concludes that malignant transformation is rare in nevus sebaceus and occurs uniquely in adulthood. On the basis of the findings, prophylactic excision of nevus sebaceus can be elective during childhood but is strongly advocated at puberty due to the increased risk of malignant transformation with time.

Sebaceous carcinoma: review of the literature

BACKGROUND

Sebaceous carcinoma is an uncommon adnexal neoplasm with a documented capability for regional and distant metastasis. Traditionally, sebaceous carcinoma has been associated with high rates of recurrence after excision.

OBJECTIVE

To review the current literature on sebaceous carcinoma and detail its epidemiology, pathogenesis, clinical presentation, histopathology, diagnostic workup, treatment, and prognosis.

MATERIALS AND METHODS

Literature review using PubMed search for articles related to sebaceous carcinoma.

RESULTS

Sebaceous carcinoma typically presents as a painless pink or yellow nodule. Diagnosis requires histopathologic examination, and immunohistochemical analysis often assists in the differentiation of sebaceous carcinoma from other benign and malignant skin neoplasms. Sebaceous carcinoma should prompt a workup for Muir-Torre syndrome. Periorbital sebaceous carcinoma has an increased tendency for regional metastasis, although cancer-specific mortality rates are similar among all anatomic locations.

CONCLUSION

Surgery is the preferred treatment for local disease. Limited data suggest that Mohs micrographic surgery may provide superior clinical outcomes, but more research is needed regarding the long-term outcomes. Radiation and systemic chemotherapy are reserved for recurrent or metastatic disease.

[Differential diagnostics of sebaceous tumors]

Sebaceous tumors are epithelial tumors with a differentiation towards sebaceous adnexal structures of the skin. They imitate the epithelial cells of mature sebaceous glands, sebaceous ducts, immature (embryonic) sebaceous structures or sebaceous glands that are not stimulated by hormones (mantle structures). This article explains the classification of sebaceous tumors on the basis of the normal histology of sebaceous glands. Clinical and histopathological criteria are given for the most important sebaceous tumors. The differential diagnosis of sebaceoma, sebaceous adenoma and various types of sebaceous carcinoma is emphasized. The importance of a specific diagnosis of adnexal tumors is demonstrated by tumor-associated syndromes with involvement of other organs (e.g., Muir-Torre syndrome and Birt-Hogg-Dubé syndrome). Furthermore, conceptional controversies, problems in differential diagnosis and the impact of immunohistochemical staining in the assessment of sebaceous tumors are considered.