|Year : 2021 | Volume
| Issue : 1 | Page : 53-54
Fibroblastic connective tissue nevus: Report of two cases
Woon- Chai Ng1, Cheng- Hsiang Hsiao2, Ya- Chu Tsai1, Shu- Hui Wang1
1 Department of Dermatology, Far Eastern Memorial Hospital, New Taipei City, Taiwan
2 Department of Anatomical Pathology, Cheng Hsin General Hospital, Taipei, Taiwan
|Date of Submission||20-Apr-2020|
|Date of Decision||24-Jul-2020|
|Date of Acceptance||07-Aug-2020|
|Date of Web Publication||24-Mar-2021|
Dr. Shu- Hui Wang
No. 21, Sec. 2, Nanya S. Rd., Banciao Dist., New Taipei City 22060
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Ng WC, Hsiao CH, Tsai YC, Wang SH. Fibroblastic connective tissue nevus: Report of two cases. Dermatol Sin 2021;39:53-4
Fibroblastic connective tissue nevus (FCTN) is a rare benign dermal mesenchymal lesion that generally affects children. Herein, we reported two cases of FCTN which presented as an asymptomatic plaque-like cutaneous lesion that subsequently verified with histopathological features.
| Case Reports|| |
An 11-year-old boy presented with an asymptomatic 1 cm × 1 cm skin-colored plaque on the left neck [Figure 1]a that gradually enlarged for few months. A total excision was performed with histopathology illustrating poorly circumscribed proliferation of spindle cells within reticular dermis. These bundles of spindle-shaped fibroblastic cells arranged in an irregular and disorderly manner with entrapping appendages. The spindle cells presented with wavy nuclei and faintly eosinophilic cytoplasm, no significant cytologic atypia or mitosis noted. Overlying papillomatous epidermis and presence of adipose tissue in reticular dermis could also be found. Immunohistochemical stains showed focal and weakly positive for CD34 and negative for smooth muscle actin (SMA) and desmin [Figure 1]b,[Figure 1]c,[Figure 1]d.
|Figure 1: (a) An 11-year-old boy presented with an asymptomatic 1 cm × 1 cm skin-colored plaque on left neck. (b) Low-power field shows poorly circumscribed proliferation of spindle cells occupied reticular dermis with entrapping appendages (×20) (c) CD34 focal and weak positive (×200) (d) smooth muscle actin negative (×200).|
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A 30-year-old woman presented with an asymptomatic 1.5 cm × 1 cm brownish plaque on the right upper back [Figure 2]a for over 10 years. Skin biopsy was performed with histopathology also illustrating poorly circumscribed of proliferation of spindle cells through reticular dermis arranged in short fascicles surrounding the adnexa. No cytologic atypia, pleomorphism, nor mitosis was found in the lesional cells. Immunohistochemical stains also showed focal weakly positive for CD34 and negative for SMA, desmin, and S100 [Figure 2]b,[Figure 2]c,[Figure 2]d.
|Figure 2: (a) An asymptomatic 1.5 cm × 1 cm brownish plaque was found on right upper back. (b) Proliferation of spindle cells through reticular dermis arranged in short fascicles surrounding the adnexa (×20)(c) The spindle cells presented with wavy nuclei and faintly eosinophilic cytoplasm (×200) (d) CD34 focal and weak positive (×200).|
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FCTN was first described by de Feraudy and Fletcher in 2012 with 25 cases aged ranging from 1 month to 58 years (median 10 years). FCTN present as a solitary slowly growing, asymptomatic plaque that most commonly found on the trunk, followed by the neck and limbs.,
Histopathologically, de Feraudy and Fletcher described FCTN as benign dermal mesenchymal lesion of fibroblastic or myofibroblastic origin that situated in reticular dermis. Tumor is composed of bundles of bland spindle-shaped cells with faintly eosinophilic cytoplasm and wavy nuclei. No cytologic atypia, pleomorphism, nor mitosis was found. These bundles were irregularly distributed throughout the reticular dermis with entrapping appendages and extending into the subcutis. Immunochemical stain for CD34 is typically weak and focal positive (87%–89%) whereas SMA is occasionally positive (47%–64%). S100 and desmin are both negative. Overlying papillomatous epidermis and superficial adipocytes are often observed.,
The most important differential diagnosis of FCTN is plaque-stage dermatofibrosarcoma protuberans. Plaque-stage DFSP is malignant fibroblastic mesenchymal skin tumor that appears as a brownish plaque predominant on trunk. Histopathologically, DFSP is located in dermis but shows diffuse irregular infiltration of subcutaneous fat in a typical lace-like pattern that running parallel to epidermis. To make distinction from FCTN, DFSP tumor is composed with uniform proliferation of atypical fibroblast arranged in a storiform pattern which CD34 staining is diffuse strong positive. Overlying papillomatous epidermis is rarely seen in DFSP. Differential diagnosis could be difficult as presentation of DFSP can sometimes be inconspicuous, so Higaki-Mori et al. suggest reverse transcriptase polymerase chain reaction to detect type 1α1 (COL1A1)/platelet-derived growth factor B-chain fusion transcripts that express in majority of DFSP could be helpful.
Dermatomyofibroma clinically demonstrated a solitary, slowly growing, asymptomatic, skin colored plaque. It normally situated on the arm and shoulder of young adults with a median age of 30 years, whereas FCTN is predominantly located on the trunk in much younger subjects. Histopathologically, dermatomyofibroma shows a proliferation of fascicles of spindle cells with pale eosinophilic cytoplasm that similar to FCTN. However, those fascicles tend to be parallel to epidermis, by contrast, fascicles in FCTN had disorderly orientation to overlying epidermis. Dermatomyofibroma is classically positive for SMA but less expressed CD34 positivity (<25%), whereas FCTN is typically positive for CD34.
Medallion-like dermal dendrocyte hamartoma (MLDD) is usually noticed since birth or infancy. Histopathologically, MLDD presented as a band-like dermal proliferation of spindle cells with strong and diffuse CD34 positive. Tumor cells are arranged in two-layer pattern with vertical orientation in the upper portions and horizontal orientation in the lower ones. Therefore, it differs from FCTN with clinical history and morphologic features.
In 2017, Lynch et al. found significant histopathologic variability from a 1-month-old boy with a biopsy-proved myofibroma on chest was subsequently demonstrated as typical FCTN over a year. Therefore, FCTN might undergo a maturation to demonstrate the typical characteristic features.
In conclusion, FCTN is a benign tumor with no potential for recurrence irrespective of margin status. It should not be confused with malignant tumor like plaque-stage DFSP as treatment of FCTN is only indicated for cosmetic issue.
The authors appreciate Prof. Ching-Chi Chi (Department of Dermatology, Chang Gung Memorial Hospital, Linkou) for his critical reading of the manuscript.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the boy's guardian and the woman have given their consent for their images and other clinical information to be reported in the journal. They understand that names and initials will not be published and due efforts will be made to conceal the identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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