Mitosis in dermatofibroma: a worrisome histopathologic sign that does not necessarily equal recurrence

A Clinicohistopathological Analysis of Cutaneous Fibrous Histiocytomas of the Finger

Background:

Cutaneous fibrous histiocytoma (CFH) is a common, benign skin tumor predominantly occurring on the extremities or trunk. However, CFH on the finger is rare.

Objective:

This study was undertaken to examine the clinicohistopathological features of CFH of the finger.

Materials and Methods:

This is a retrospective study of 12 CFHs located on fingers in a tertiary hospital in Korea. All case slides were retrieved from saved files.

Results:

Ages of the CHF of the finger affected individuals ranged from 9 to 48 years with a male-to-female ratio of 1.4:1. Picker's nodule or wart was the most common clinical diagnosis. In only 2 out of the 12 cases was the pre-biopsy diagnosis of CFH ventured. Fibrocollagenous type was the most common histological type. Majority of the cases were mitotically inactive, exhibiting only 0–1 mitoses per high-power field and there was no recurrence. Tumor cells were uniformly CD34 negative.

Conclusion:

Because CFH can resemble malignancies including dermatofibrosarcoma protuberans, a lack of familiarity with the occurrence of CFH of the finger may lead to more aggressive treatment. Dermatologists should include CFH in their differential diagnosis of circumscribed nodules on the fingers to ensure proper management.

Dermatofibrosarcoma protuberans associated with trauma: A case report

A case of dermatofibrosarcoma protuberans (DFSP) in a 22-year old female associated with blunt trauma of the mid-upper back is presented in the current study with a review of the literature. DFSP is a rare slow growing sarcoma of the soft tissue most commonly seen on the trunk and upper extremities with a low to intermediate grade malignant potential, high chance of local invasion and a high local recurrence rate. The literature search revealed that both non-congenital mutation as well as trauma serve a role in the development of this dermal neoplasm, but the exact mechanism by which trauma may predispose to development of DFSP is unknown. However, it seems intuitive that chronic inflammation and stimulation of the immune system at a local level may trigger the immunopathologic changes that could lead to the malignant transformation of dermal cells. Future research into the relationship between trauma and DFSP on a cellular level is required, as there appears to be a direct link present.

Phosphohistone-H3 and Ki67: Useful Markers in Differentiating Dermatofibroma From Dermatofibrosarcoma Protuberans and Atypical Fibrohistiocytic Lesions

Dermatofibromas (DF) are common, benign, skin tumors, usually easily differentiated from dermatofibrosarcoma protuberans (DFSP) by the presence of a relative low cellularity, lesser degree of infiltration of subcutaneous tissue, and immunohistochemical pattern (eg, FXIIIa in DF and CD34 in DFSP). Atypical fibrohistiocytic lesions (AFL) have features intermediate to DF and DFSP (trunk location, storiform pattern, infiltration of the subcutaneous tissue, and focal expression of both CD34 and Factor XIIIa). It is unclear if mitotic counts/degree of proliferation is helpful to distinguish DF from DFSP. To study the mitotic rate and proliferation index in DF, AFL/DFSP, anti-ki67, and anti-PHH3 were performed on 10 cases of DF (including 4 cellular DF), 10 standard DFSP, and 2 AFL. The proliferation index and mitotic figures were counted per square millimeter in a "hotspot" (in a fashion similar to mitotic counts in melanoma). All cases of DF showed much higher Ki67 proliferation index (P = 0.0001) along with increased mitotic figures both on H&E and with anti-PHH3 (P = 0.0001) when compared to AFL/DFSP. Our data indicate that DF has a higher proliferation index and mitotic counts when compared to superficial/peripheral portion of AFL and DFSP. This finding may be helpful in the differential diagnosis among these fibrohistiocytic lesions.

Sebaceous induction in dermatofibroma: a common feature of dermatofibromas on the shoulder

BACKGROUND

Dermatofibroma (DF) has multiple histopathological variants and overlying acanthosis, hyperkeratosis and hyperpigmentation are often present. We have frequently observed sebaceous induction in DFs on the shoulder and wanted to assess if this is a site-specific finding.

METHODS

We prospectively collected 100 DFs and assessed for sebaceous induction, the histopathologic pattern of the DF and any associated-epidermal changes. We retrospectively searched for DFs with sebaceous induction to assess the anatomic site of the biopsy.

RESULTS

In the 100 prospectively collected DFs, 49% occurred on the lower extremities, 39% on the upper extremities, 10% on the trunk and 2% on the head. Sebaceous induction was present in 16 DFs, 81% of which occurred on or near the shoulder. The most common variant was fibrocollagenous DF (64%), including in DFs with sebaceous induction. The retrospective search for DFs with sebaceous induction found 19 cases in which 95% occurred on the shoulder area. Sclerotic pattern DFs were most common in this retrospective cohort (47%), and seborrheic keratosis-like hyperplasia occurred in 100% of these cases.

CONCLUSION

DFs occurring on the shoulder have a high incidence of sebaceous induction with seborrheic keratosis-like epidermal hyperplasia and a fibrocollagenous or sclerotic pattern.

Dermatofibroma of the face: a clinicopathologic study of 20 cases

INTRODUCTION

Dermatofibroma is one of the most common benign skin tumors. It typically develops on the lower limbs between the third and fifth decade of life and is more common in women. Clinical diagnosis is often straightforward. Dermatofibromas are associated with a very low rate of local recurrence following excision.

OBJECTIVES

To describe the clinical and histologic features of dermatofibroma of the face based on our experience.

MATERIALS AND METHODS

Descriptive retrospective study of the clinicopathologic features of dermatofibromas of the face diagnosed at the dermatology department of Hospital General Universitario de Valencia between 1990 and 2012.

RESULTS

Twenty cases of dermatofibroma of the face (1.11% of all dermatofibromas diagnosed) were studied. The age at onset varied widely, from 28 to 84 years. The mean age at onset was 57.15 years and the median was 54 years. There were 11 women and 9 men. Mean follow-up was 83 months and there were no local recurrences. All the tumors were confined to the papillary and reticular dermis and the storiform pattern was the most common growth pattern observed.

CONCLUSIONS

This study of facial dermatofibromas diagnosed at our hospital over a period of 22 years suggests that the face is an uncommon site but that dermatofibromas in this location behave similarly to those occurring elsewhere on the body.