Cancer, Premalignant Fibroepithelial (Pinkus Tumor)


Article Author:
Karlin Sevensma


Article Editor:
Kamleshun Ramphul


Editors In Chief:
Sebastiano Cassaro
Joseph Lee
Tanya Egodage


Managing Editors:
Orawan Chaigasame
Carrie Smith
Abdul Waheed
Frank Smeeks
Kristina Soman-Faulkner
Benjamin Eovaldi
Radia Jamil
Sobhan Daneshfar
Pritesh Sheth
Hassam Zulfiqar
Steve Bhimji
John Shell
Matthew Varacallo
Ahmad Malik
Mark Pellegrini
James Hughes
Beata Beatty
Richard Ciresi
Hajira Basit
Phillip Hynes
Kavin Sugumar


Updated:
12/2/2018 12:11:07 AM

Introduction

In 1953, Dr. Herman Pinkus first described the fibroepithelial tumor of Pinkus (FEP) as a pre-malignant epithelial tumor. Although there has been some dispute over the classification of FEP, its histologic appearance is unique and distinguishes it from other fibroepithelial tumors. Several important distinctions can be made between FEP and basal cell carcinoma (BCC.) Most notable is the presence of Merkel cells in FEP and the absence of those cells in BCC. FEP also occurs more frequently in females and has no association with sun exposure. It typically occurs on the lower trunk; whereas, BCC is more common in sun-exposed areas of the body. [1] From a prognostic standpoint, FEP does not have an aggressive course and has not been reported to invade or metastasize. [2] Basal cell carcinoma, on the other hand, can invade and metastasize if left untreated. 

Etiology

The origin of FEP is enigmatic. Some have suggested that it develops in a seborrheic keratosis. [3] Others have suggested that it represents the eccrine spread of a basal cell carcinoma. This theory is based upon the histopathologic observation of small CEA-positive gland-like structures in the fine anastomosing network of cells that surround the basaloid nubbins of FEP as well as the observed resemblance of the fine anastomosing strands to some reactive eccrine sweat gland changes. [4] [5] This concept has been refuted by other authors who reject the idea of basal cell carcinoma spreading along eccrine ducts, noting that eccrine ducts grow vertically and rarely anastomose with each other, making lateral spread challenging. [6] Other work suggests that that the microscopically-fine anastomosing strands of FEP are PHLDA1 positive and represent a “tumor-specific type of epidermal hyperplasia” within which the basaloid nubbins are nestled, giving FEP its characteristic fenestrated appearance. The fine anastomosing strands also exhibit a high content of Merkel cells. The basaloid nubbins, which are both low in Merkel cells and PHLDA1 negative, are postulated to potentially give rise to nodular BCC, which is not uncommonly seen adjacent to or in continuity with FEP. In addition, the basaloid nubbins stain positive for nestin, which is a marker that is positive in the stroma of BCC. [7]

Epidemiology

It is considered a rare tumor, though some authors suggest that FEP may not be as rare as it seems, and its rarity may be a product of misdiagnosis. [8] FEP typically presents in males between age 40 and 60 but can be found at any age. It has been reported in children. [2]

Pathophysiology

FEP is not related to sun exposure. Development of FEP may be related to activation of the Hedgehog pathway by mutation of PTCH (patched transmembrane molecule), which decreases the negative regulation of the Hedgehog pathway. This is known to occur in some basal cell carcinomas and may also play a role in the development of FEP. Ionizing radiation has also been implicated. [1]

Histopathology

FEP exhibits a “fenestrated pattern” consisting of islands of the tumor, often referred to as nests, holes or nubbins surrounded by thin anastomosing strands of basaloid or squamous cells. [9] FEP occurs in the dermis, proliferating and pushing the epidermis upward, forming the clinical appearance of a papillary or polypoid growth. In its isolated form, that is, without an accompanying nodular basal cell carcinoma, FEP does not invade the subcutis. [1]

History and Physical

FEP typically presents as a single or multiple papillary or polypoid growths on the skin. The tumor may be pink, tan, brown or skin-colored. It can be sub-divided into pigmented and non-pigmented types based upon gross coloration. There may also be some superficial excoriation or erosion, but typically not deep ulceration. [8] FEP usually occurs on the trunk and is not associated with ultraviolet (UV) light exposure. [1]

Evaluation

Some authors advocate for dermoscopy and reflectance confocal microscopy (RCM) to aid in the diagnosis of these lesions. On dermoscopy, one can see finely branching short vessels as well as punctate vessels around the periphery. If a polarized light source is used, short, white streaks called crystalline, or chrysalis structures can be seen. In pigmented lesions, dermoscopy can reveal gray-brown areas and/or gray-blue dots, which suggests FEP. [8] In a case series evaluating dermoscopy, one author reported an accurate diagnosis of FEP in nine out of ten patients. [10] Reflectance confocal microscopy of FEP can reveal the classic “fenestrated pattern” at the dermo-epidermal junction showing “holes” of fibrous stroma surrounded by fine cords of palisading cells. This correlates well to the histologic appearance of these tumors. [9] A histopathologic analysis makes diagnosis following excision. [1]

Treatment / Management

Treatment involves recognition of the lesion followed by complete excision. Because of its potentially benign gross appearance, a fibroepithelial tumor of Pinkus may be an under-recognized and under-reported condition. Electrodesiccation and curettage of the lesion may be effective, but since this is a rare and likely under-recognized tumor, evidence for the efficacy of these treatments is not available. Mohs surgery has been performed for this type of tumor and is indicated if the anatomic location on the body limits clear margins. There is no role for chemotherapy or radiation. FEP has not been reported to result in patient death. [1]

Differential Diagnosis

The differential diagnosis of a skin lesion which is FEP can include many other pathologies, both benign and malignant. When FEP is mistaken for a benign lesion, such as acrochordon, seborrheic keratosis, dermal nevus, pedunculated fibroma, lipomatous nevus or neurofibroma, this delays biopsy. Since many benign skin lesions are treated without submitting tissue for biopsy, the diagnosis of FEP may never be made. [1]

Prognosis

It generally runs an indolent course. Prognosis is generally excellent and excision is considered curative. [1]

Complications

The controversy about whether FEP is a subtype of basal cell carcinoma or a trichoblastoma is ongoing, though the most recent literature supports FEP as a subtype of basal cell carcinoma. The presence of Merkel cells and weak expression of the p53 oncogene in both FEP and trichoblastoma leads to the association of the two entities and separates them from BCC. [1] On the other hand, androgen receptor presence in FEP is similar to BCC, unlike trichoepitheliomas and trichoblastomas, which do not express androgen receptors, suggesting that FEP is a variant of BCC. [11] More recent work using the stem cell marker PHLDA1 offers an embryologic explanation for the presence of Merkel cells in FEP and provides this as evidence that FEP is truly a subtype of basal cell carcinoma. [7] Whether or not one considers FEP a subtype of BCC or a trichoblastoma has a direct bearing on whether or not one considers FEP malignant or benign, which is also controversial. Its clinical behavior suggests benignity unless FEP happens to be found in association with a nodular basal cell carcinoma, which has been reported. [2]

Deterrence and Patient Education

Although development of fibroepthelioma of Pinkus is not related to sun exposure, it is vital to properly educate all patients with basal cell carcinoma about the proper use of sunscreens, the avoidance of excessive sun exposure and the dangers of tanning.

Enhancing Healthcare Team Outcomes

Evidence related to diagnosis and management of Fiborepithelial Tumors of Pinkus is limited to Class III, IV and V evidence, due to the rarity of the condition.


Interested in Participating?

We are looking for contributors to author, edit, and peer review our vast library of review articles and multiple choice questions. In as little as 2-3 hours you can make a significant contribution to your specialty. In return for a small amount of your time, you will receive free access to all content and you will be published as an author or editor in eBooks, apps, online CME/CE activities, and an online Learning Management System for students, teachers, and program directors that allows access to review materials in over 500 specialties.

Improve Content - Become an Author or Editor

This is an academic project designed to provide inexpensive peer-reviewed Apps, eBooks, and very soon an online CME/CE system to help students identify weaknesses and improve knowledge. We would like you to consider being an author or editor. Please click here to learn more. Thank you for you for your interest, the StatPearls Publishing Editorial Team.

Cancer, Premalignant Fibroepithelial (Pinkus Tumor) - Questions

Take a quiz of the questions on this article.

Take Quiz
Controversy exists in describing fibroepithelial tumor of Pinkus (FEP). Some feel that it is a variant of basal cell carcinoma (BCC) and others feel it is more closely related to trichoepithelioma/trichoblastoma. Which of the following is evidence supporting FEP as a variant of BCC?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A patient presents with a light brown, raised, 1.5 cm nodule on the abdomen. Dermoscopy followed by biopsy is performed and fibroepithelial tumor of Pinkus is identified. Which of the following is true?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A patient presents for evaluation of a 2 cm, raised, skin-colored nodule on their trunk. The lesion has been there for one year and has been growing for that time period. Dermoscopy is recommended to evaluate the lesion. Advocates for the use of dermoscopy to evaluate fibroepithelial tumor of Pinkus describe the dermoscopic appearance of the lesions as demonstrating which of the following?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A patient presents with a raised, skin-colored 1 cm skin lesion on the lower abdomen. It is firm, but not ulcerated or irregular. A decision is made for biopsy. The pathology returns as “fibroepithelial tumor of Pinkus, incompletely excised.” What is the most appropriate treatment for this patient?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which of the following is not a feature associated with a high risk of recurrence of basal cell carcinoma.



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up

Cancer, Premalignant Fibroepithelial (Pinkus Tumor) - References

References

Longo C,Soyer HP,Pepe P,Casari A,Wurm EM,Guitera P,Pellacani G, In vivo confocal microscopic pattern of fibroepithelioma of pinkus. Archives of dermatology. 2012 Apr     [PubMed]
Su MW,Fromer E,Fung MA, Fibroepithelioma of pinkus. Dermatology online journal. 2006 Sep 8     [PubMed]
Reggiani C,Zalaudek I,Piana S,Longo C,Argenziano G,Lallas A,Pellacani G,Moscarella E, Fibroepithelioma of Pinkus: case reports and review of the literature. Dermatology (Basel, Switzerland). 2013     [PubMed]
Gutte RM, Fibroepithelioma of Pinkus: a distinctive variant of trichoblastic carcinoma. Indian journal of dermatology, venereology and leprology. 2013 Sep-Oct     [PubMed]
Katona TM,Ravis SM,Perkins SM,Moores WB,Billings SD, Expression of androgen receptor by fibroepithelioma of Pinkus: evidence supporting classification as a basal cell carcinoma variant? The American Journal of dermatopathology. 2007 Feb     [PubMed]
Sellheyer K,Nelson P,Kutzner H, Fibroepithelioma of Pinkus is a true basal cell carcinoma developing in association with a newly identified tumour-specific type of epidermal hyperplasia. The British journal of dermatology. 2012 Jan     [PubMed]
Ackerman AB,Gottlieb GJ, Fibroepithelial tumor of pinkus is trichoblastic (Basal-cell) carcinoma. The American Journal of dermatopathology. 2005 Apr     [PubMed]
Stern JB,Haupt HM,Smith RR, Fibroepithelioma of Pinkus. Eccrine duct spread of basal cell carcinoma. The American Journal of dermatopathology. 1994 Dec     [PubMed]
Kurokawa I,Yokoyama T,Nishimura K,Hakamada A,Isoda K,Yamanaka K,Tsubura A,Mizutani H, Pinkus tumor may originate from intraepidermal eccrine ducts and proliferate in the dermis. Oncology reports. 2007 Jan     [PubMed]
Sina B,Kauffman CL, Fibroepithelioma of Pinkus: eccrine duct spread of basal cell carcinoma. The American Journal of dermatopathology. 1995 Dec     [PubMed]
Zalaudek I,Ferrara G,Broganelli P,Moscarella E,Mordente I,Giacomel J,Argenziano G, Dermoscopy patterns of fibroepithelioma of pinkus. Archives of dermatology. 2006 Oct     [PubMed]

Disclaimer

The intent of StatPearls is to provide practice questions and explanations to assist you in identifying and resolving knowledge deficits. These questions and explanations are not intended to be a source of the knowledge base of all of medicine, nor is it intended to be a board or certification review of Surgery-General. The authors or editors do not warrant the information is complete or accurate. The reader is encouraged to verify each answer and explanation in several references. All drug indications and dosages should be verified before administration.

StatPearls offers the most comprehensive database of free multiple-choice questions with explanations and short review chapters ever developed. This system helps physicians, medical students, dentists, nurses, pharmacists, and allied health professionals identify education deficits and learn new concepts. StatPearls is not a board or certification review system for Surgery-General, it is a learning system that you can use to help improve your knowledge base of medicine for life-long learning. StatPearls will help you identify your weaknesses so that when you are ready to study for a board or certification exam in Surgery-General, you will already be prepared.

Our content is updated continuously through a multi-step peer review process that will help you be prepared and review for a thorough knowledge of Surgery-General. When it is time for the Surgery-General board and certification exam, you will already be ready. Besides online study quizzes, we also publish our peer-reviewed content in eBooks and mobile Apps. We also offer inexpensive CME/CE, so our content can be used to attain education credits while you study Surgery-General.