Home About us Editorial board Search Ahead of print Current issue Archives Submit article Instructions Subscribe Contacts Login 
Print this page Email this page Users Online: 817

 Table of Contents  
CASE REPORT
Year : 2014  |  Volume : 3  |  Issue : 2  |  Page : 111-113

An interesting case report of ulcerated proliferating pilar tumor (PPT) mimicking squamous cell carcinoma


Department of Pathology, Maharaja Institute of Medical Sciences, Nellimarla, Vizianagaram, Andhra Pradesh, India

Date of Web Publication20-Jun-2014

Correspondence Address:
Ramesh Uppada
Assistant professor, Maharaja Institute of Medical Sciences, Nellimarla, Vizianagaram, Andhra Pradesh
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2277-8632.134858

Rights and Permissions
  Abstract 

Proliferating pilar tumor (PPT) is a rare neoplasm arising from the isthmus of the outer root sheath of the hair follicle, commonly called a proliferating trichilemmal cyst. It is described as a well-circumscribed dermal or subcutaneous neoplasm with squamoid cytologic features and trichilemmal type of keratinization. PPTs most commonly occur on the scalp during the 4 th -8 th decades of life with distinct predilection for women. They typically undergo slow but progressive enlargement over several months to years, yielding lobulated and exophytic masses that occasionally ulcerate mimicking squamous cell carcinoma both grossly and microscopically; posing a diagnostic challenge to young surgeons, dermatologists, and pathologists. Here we report an interesting case of an ulcerated PPT which was diagnosed cytologically as benign adnexal tumor and confirmed histopathologically as benign PPT. Ulcerated PPT is an important differential diagnosis of ulcerated scalp swellings and needs to be differentiated from squamous cell carcinoma.

Keywords: Squamous cell carcinoma, ulcerated proliferating pilar tumor, exophytic mass


How to cite this article:
Uppada R, Rout S, Bora N, Pullela RV. An interesting case report of ulcerated proliferating pilar tumor (PPT) mimicking squamous cell carcinoma. J NTR Univ Health Sci 2014;3:111-3

How to cite this URL:
Uppada R, Rout S, Bora N, Pullela RV. An interesting case report of ulcerated proliferating pilar tumor (PPT) mimicking squamous cell carcinoma. J NTR Univ Health Sci [serial online] 2014 [cited 2019 Aug 20];3:111-3. Available from: http://www.jdrntruhs.org/text.asp?2014/3/2/111/134858


  Introduction Top


A proliferating pilar tumor (PPT) is a rare neoplasm arising from the isthmus of the outer root sheath of the hair follicle, commonly called as proliferating trichilemmal cyst and was first described by Jones [1] in 1966. It is a well-circumscribed dermal or subcutaneous neoplasm with squamoid cytologic features and trichilemmal type of keratinization. [2] Most tumors arise within a preexisting pilar cyst. PPTs most commonly occur on the scalp during the 4 th -8 th decades of life with distinct predilection for women. [3] They typically undergo slow but progressive enlargement over several months to years, yielding lobulated and exophytic masses that occasionally ulcerate. [2] These ulcerated PPTs can greatly resemble squamous cell carcinoma both clinically and microscopically posing a diagnostic challenge to young surgeons, dermatologists, and pathologists. PPTs can undergo neoplastic transformation to malignant PPTs. [3],[4],[5] Here we report a case of an ulcerated PPT which was diagnosed cytologically as benign adnexal tumor and confirmed histopathologically as benign PPT.


  Case report Top


A 45-year-old female presented with a swelling over right parietal region of scalp for last 1.5 year duration. On examination, swelling was measuring about 3.5 × 3 cm with ulcerated surface that was bleeding on touch and cystic to firm in consistency.

Cytology

Fine needle aspiration cytology (FNAC) was done from the scalp swelling. The smears were moderately cellular with presence of keratinous material, both anucleate and nucleated squamous cells without any significant cytological atypia [Figure 1]. A diagnosis of benign adnexal neoplasm, probably of pilar origin was given.
Figure 1: Cytology smears showing blotchy keratinous material in the aspirate (H and E, 400×). Mature nucleate squames and also anucleate squames seen in other parts of the slide

Click here to view


Pathological findings

On gross examination, the tumor was a hairy, skin covered nodular mass of size 3.5 × 3 × 1.5 cm with surface ulceration. The cut surface was showing a well-circumscribed, lobulated, greyish white mass [Figure 2].
Figure 2: Cut-section of the ulcerated tumor shows a wellcircumscribed, lobulated, greyish white mass in the dermis

Click here to view


Histopathological examination showed surface epidermis with ulceration, acanthosis, and lymphocytic infiltration. A well-demarcated, lobulated mass was present in the lower dermis [Figure 3]. The mass consisted of palisading peripheral cell layer with central squamous cells showing abrupt trichilemmal type of keratinization, forming extensive glassy keratinous material. There are also cystic spaces lined by squamous cells and vacuolated cells, filled with keratinous material resembling squamous pearls [Figure 4]. Focal calcification within keratinous material is seen.
Figure 3: Shows a well-capsulated nodule in the dermis made up of squamoid cells arranged in lobular and diffuse pattern (hematoxylin and eosin (H and E), 400×). This image represents the solid area in the tumor

Click here to view
Figure 4: Cystic spaces in tumor lined by outer vacuolated cells and the lumen filled with keratinous material. Solid areas show squamous pearls mimicking malignancy, but without any significant atypia (H and E, 100×)

Click here to view



  Discussion Top


A PPT usually arises in the setting of single or multiple pilar cysts. A rapid increase in size signals the neoplastic transformation of the cyst into a PPT. The underlying stimulus for this transformation is not known, but thought to be due to trauma, irritation, or chronic inflammation. Lesions are usually single and firm to soft painless nodules. The most common location is the scalp (90%). Other reported sites include back, chest, groin, gluteal region, [6] thigh, vulva, [7] and eyelid. [8] Inflammation, ulceration, bleeding, and/or yellowish discharge may occur. The lesion may grow into a large, elevated, lobulated mass that may undergo ulceration; and thus greatly resemble squamous cell carcinoma. [9] The neoplasm is well circumscribed, with islands of squamous epithelium undergoing trichilemmal keratinization which is histological hallmark of PPTs. Ye et al., [10] proposed a tentative stratification of PPTs into benign (group 1), low grade malignancy (group 2), and high grade malignancy (group 3). Group 1 PPTs are circumscribed with "pushing" margins and have modest nuclear atypia with absence of mitoses, necrosis, and angioinvasion; group 2 PPTs are similar to group 1, but showed irregular, locally invasive margins with involvement of the deep dermis, and subcutis; group 3 PPTs manifested invasive growth patterns, marked nuclear atypia, atypical mitosis, and geographic necrosis with or without involvement of nerves or blood vessels. It has been found that local regrowth is common with group 2 PPTs, while group 3 PPTs have metastatic potential. [10] Determining the malignant potential of a PPT may be challenging. Malignant PPTs are more likely to stain positive with p53 and Ki-67 compared to benign PPTs and trichilemmal cysts. [11]

The common differential diagnoses of PPTs are epidermoid cyst, cylindroma, and squamous cell carcinoma. [9] Cytologically, PPTs have relatively less amount of keratin and nests of squamoid and basaloid cells with abrupt anucleate keratinization; [12] whereas epidermoid cysts show a cleaner background with high cellularity of many nucleate and anucleate squmaes. [12] The important differential diagnosis for ulcerated PPT is squamous cell carcinoma and it can be ruled out by the absence of extensive areas of severe atypia and absence of invasion into the surrounding tissue. [10] In contrast to ordinary trichilemmal cyst, PPTs in addition show changes resembling keratinization of the follicular infundibulum giving rise to horn pearls, vacuolated cells containing glycogen like the outer root sheath cells, and prominent glassy layer of collagen. [13]

The prognosis of PPTs is excellent with complete excision. Local recurrences are common in tumors which are incompletely excised. Cases showing malignant transformation and invasion into cerebral sinuses causing death have been reported.

Our case emphasizes the necessity for detailed clinical examination along with pathological correlation to arrive at the diagnosis of ulcerated PPT which mimicks squamous cell carcinoma.

 
  References Top

1.Jones EW. Proliferating epidermoid cysts. Arch Dermatol 1966;94:11-9.  Back to cited text no. 1
[PUBMED]    
2.Wick MR, Swanson PE. Cutaneous adnexal tumors: A guide to pathologic diagnosis. Chicago: ASCP Press; 1991. p. 113-68.  Back to cited text no. 2
    
3.Sau P, Graham JH, Helwig EB. Proliferating epithelial cysts. Clinicopathological analysis of 96 cases. J Cutan Pathol 1995;22:394-406.  Back to cited text no. 3
    
4.Rutty GN, Richman PI, Laing JH. Malignant change in trichilemmal cysts: A study of cell proliferation and DNA content. Histopathology 1992;21:465-8.  Back to cited text no. 4
    
5.Weiss J, Heine M, Grimmel M, Jung EG. Malignant proliferating trichilemmal cyst. J Am Acad Dermatol 1995;32:870-3.  Back to cited text no. 5
    
6.Karaca S, Kulac M, Dilek FH, Polat C, Yilmaz S. Giant proliferating trichilemmal tumor of the gluteal region. Dermatol Surg 2005;31:1734-6.  Back to cited text no. 6
    
7.Avinoach I, Zirkin HJ, Glezerman M. Proliferating trichilemmal tumor of the vulva. Case report and review of the literature. Int J Gynecol Pathol 1989;8:163-8.  Back to cited text no. 7
    
8.Kang SJ, Wojno TH, Grossniklaus HE. Proliferating trichilemmal cyst of the eyelid. Am J Ophthalmol 2007;143:1065-7.  Back to cited text no. 8
    
9.Brownstein MH, Arluk DJ. Proliferating trichilemmal cyst: A simulant of squamous cell carcinoma. Cancer 1981;48:1207-14.  Back to cited text no. 9
[PUBMED]    
10.Ye J, Nappi O, Swanson PE, Patterson JW, Wick MR. Proliferating pilar tumors: A clinicopathologic study of 76 cases with a proposal for definition of benign and malignant variants. Am J Clin Pathol 2004;122:566-74.  Back to cited text no. 10
    
11.Chaichamnan K, Satayasoontorn K, Puttanupaab S, Attainsee A. Malignant proliferating trichilemmal tumors with CD34 expression. J Med Assoc Thai 2010;93 Suppl 6:S28-34.  Back to cited text no. 11
    
12.Shet T, Rege J, Naik L. Cytodiagnosis of simple and proliferating trichilemmal cysts. Acta Cytol 2001;45:582-8.  Back to cited text no. 12
    
13.Lever WF. Tumors of the epidermal appendages. In: Lever's Histopathology of the Skin. 8 th ed. Philadelphia: Lippincott Williams and Wilkins; 1997. p. 759-61.  Back to cited text no. 13
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4]



 

Top
 
 
  Search
 
Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

 
  In this article
Abstract
Introduction
Case report
Discussion
References
Article Figures

 Article Access Statistics
    Viewed2406    
    Printed43    
    Emailed0    
    PDF Downloaded196    
    Comments [Add]    

Recommend this journal