Benign lesions
Richard P. Usatine, Daniel L. Stulberg, Graham B. Colver in Cutaneous Cryosurgery, 2014
If the diagnosis of dermatofibroma is in doubt the nodule should be excised, but diagnosis is often possible by pinching the nodule and observing the positive dimple sign and noting the hyperpigmented halo and central scarlike structures (Figure 8.11). Dermoscopic findings are also very helpful (see Appendix C). When the diagnosis is certain, it can be left untouched, excised, or frozen with liquid nitrogen. Certainly the nodular component can be flattened with cryosurgery but a pale area may be left behind (Figure 8.11). In one study each dermatofibroma was treated by liquid nitrogen cryospray for about 30 s to produce a visible freezing of the tumor and a 2-mm border of surrounding skin.7 The overall response to therapy, as assessed by the patient, was excellent or good in 32 out of 35. The results assessed by an observer were excellent or good in 31 out of 35 lesions: 15 patients required 1 treatment, 16 patients 2 treatments and 4 patients 3 treatments.7 A 30-s freeze time is the same aggressive freeze time used to treat basal cell carcinomas, and a local lidocaine injection should be offered for anesthesia before such treatment.
Soft Tissues
Joseph Kovi, Hung Dinh Duong in Frozen Section In Surgical Pathology: An Atlas, 2019
DIFFERENTIAL DIAGNOSIS: ClinicalDermatofibrosarcoma protuberans should be distinguished from dermatofibroma. See differential diagnosis, clinical, under dermatofibroma.*MicroscopicThe differential diagnosis of dermatofibrosarcoma protuberans and dermatofibroma is discussed under differential diagnosis, microscopic, of dermatofibroma.**
Histopathology
Dimitris Rigopoulos, Alexander C. Katoulis in Hyperpigmentation, 2017
Dermatofibroma is a common benign fibrohistiocytic lesion that is considered to develop as a reaction to an insect bite or other focal trauma. Clinically, it presents as an indurated nodule with an often hyperpigmented surface. The hyperpigmentation corresponds to increased pigmentation of basal keratinocytes, which is often accompanied by acanthosis or seborrheic keratosis–like changes.32 The epidermal changes above dermatofibroma occasionally also include induction of follicular or sebaceous adnexal structures. They are considered to result from mediators released by fibroblasts that interact with epidermal cells.
Deep fibrous histiocytoma of the index finger: a case report
Published in Case Reports in Plastic Surgery and Hand Surgery, 2023
Hiroki Shibayama, Yuichiro Matsui, Daisuke Kawamura, Daisuke Momma, Takeshi Endo, Yuki Matsui, Yasutaka Yawaka, Kanako C. Hatanaka, Emi Takakuwa, Hirokazu Sugino, Yutaka Hatanaka, Tadashi Hasegawa, Norimasa Iwasaki
HE staining showed that the tumor was relatively well-circumscribed and contained no cutaneous adnexa (Figure 2(b, c)). The lesions had a high cellular density rather than fibrous tissues, with spindle-shaped cells mainly seen in a storiform pattern and partially in a short fascicular pattern. There was no nuclear pleomorphism or hyperchromasia, and no staghorn vessels. The lesions did not have giant cells, hemosiderin, a hemangiopericytoma-like vascular pattern, or a slit-like pattern. Immunohistochemical staining revealed CD68 and factor XIIIa-positive histiocytes (Figure 2(d, e)). CD34 was negative and α-smooth muscle actin (α-SMA) was positive (Figure 2(f)). However, the signal transducer and activator of transcription 6 (STAT6), S100 protein, and desmin were negative. On the basis of these findings, we ruled out fibroma of the tendon sheath, tenosynovial giant cell tumor, DFSP, and SFT, and the diagnosis of DFH was confirmed. Dermatofibroma was ruled out by findings of the normal overlying skin, easy dissection from the skin and no cutaneous adnexa in HE staining. Because DFH rarely occurs in the hand, we performed additional cytogenetic analysis.
Unique histopathologic features of the eyelid dermatofibroma
Published in Orbit, 2019
Aliaa H. Abdelhakim, Kristen E. Dunbar, Kyle J. Godfrey, Cristina Abascal Ananza, David N. Silvers, Michael Kazim
Dermatofibroma (also known as fibrous histiocytoma) is a common skin lesion arising from the dermis. Generally considered to be a benign neoplasm of fibroblastic cells admixed with collagen and histiocytes, it develops through a reactive process, or in response to cutaneous trauma. Clinically, it most often appears as solitary, firm papule with a red, brown or tan hue, and may be associated with pruritus.1
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