Brief Report

589https://doi.org/10.5021/ad.2021.33.6.589

Dear Editor:A 62-year-old female presented with an asymptomatic subcu-taneous nodule on the left cheek. She had received 4 sessions of hyaluronic acid (HA) filler injections in both nasolabial folds 4 years prior; a year later, the lesion had started to enlarge gradually. Physical examination revealed a well-defined 1.0 cm×0.5 cm-sized skin-colored to bluish subcutaneous nodule on the left nasolabial fold (Fig. 1A). We received the patient’s consent form about publishing all photographic materials. As a granulomatous reaction after HA filler injection was suspected, punch biopsy was performed. The biopsy contained a piece of hard foreign material resembling pencil lead, approximately 0.8-cm long (Fig. 1B). Histopathologic findings showed granu-lomatous inflammations with fibrosis, which was composed of histiocytes, foreign body giant cells, and dispersed black pigment throughout the dermis (Fig. 1C, D). The alcian blue stain for the detection of HA was negative. During a second in-terview with the patient, she recalled having a pencil-tip injury as an elementary school student. The patient was diagnosed with pencil-core granuloma and the residual tissue was excised.

There has been no evidence of recurrences and complications for 2 years.

Pencil-core granuloma (graphite granuloma) is a delayed foreign body reaction to retained fragments of pencil lead. Al-though pencil lead is generally known to be biologically inert for a long time, individual components such as graphite, clay, and various waxes could induce a tissue reaction1. The mecha-nism for the formation of pencil-core granuloma remains unclear. However, it is thought that the dispersal of graphite particles, which is caused by repeated mechanical stimuli, re-sults in an accumulation of macrophages; these accumulated macrophages release various cytokines and growth factors that induce tissue reactions2. The time lag from pencil-tip injury to granuloma formation ranges from 1.5 to 58 years. This long lag period suggests that a long time is often required for the break-down of graphite to a critical size, dispersal of particles to the interstitium, and granuloma formation1,3.

To our knowledge, there are only three cases of pencil-core granuloma in the Korean literature (Table 1)4,5. In two previ-ous cases, the lesion was located on the extremities, and the lag periods were shorter than in our case. We believe that less fre-quent mechanical stimulation on the face compared to that on extremities is the reason for delayed facial occurrence. Interest-ingly, in our case, the lesion presented after HA filler injections, which suggests that not only repeated injection procedures but also filler materials may trigger the graphite breakdown and ac-celerate the granuloma formation.

In conclusion, physicians should be aware that pencil lead may cause delayed granulomatous reactions. All pencil-tip injuries should be assessed carefully and complete removal of remnant graphite from the wound is recommended.

Brief Report Annals of Dermatology 2021;Annals of Dermatology 2021;3333((66)) • https://doi.org/10.5021/ad.2021.33.6.589 • https://doi.org/10.5021/ad.2021.33.6.589

A Case of Pencil-Core Granuloma after Hyaluronic Acid Filler InjectionYong Woo Oh, Dong Hee Kim, Byeong Hak Seo, Ho Seok Suh, Yu Sung Choi

Department of Dermatology, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea

Received June 1, 2020 Revised July 29, 2020Accepted August 4, 2020

Corresponding AuthorYu Sung ChoiDepartment of Dermatology, Ulsan University Hospital, University of Ulsan College of Medicine, 877 Bangeojinsunhwando-ro, Dong-gu, Ulsan 44033, KoreaTel: +82-52-250-7090Fax: +82-52-250-7155E-mail: uuhderma@daum.nethttps://orcid.org/0000-0001-8308-4091

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Brief Report

CONFLICTS OF INTEREST

The authors have nothing to disclose.

FUNDING SOURCE

None.

ORCID

Yong Woo Oh, https://orcid.org/0000-0001-7169-7798

Dong Hee Kim, https://orcid.org/0000-0002-7727-1429 Byeong Hak Seo, https://orcid.org/0000-0002-7300-8236 Ho Seok Suh, https://orcid.org/0000-0002-6781-5429 Yu Sung Choi, https://orcid.org/0000-0001-8308-4091

REFERENCES

1. Yoshitatsu S, Takagi T. A case of giant pencil-core granuloma. J Der-

matol 2000;27:329-332.

2. Terasawa N, Kishimoto S, Kibe Y, Takenaka H, Yasuno H. Graphite

foreign body granuloma. Br J Dermatol 1999;141:774-776.

3. Fukunaga Y, Hashimoto I, Nakanishi H, Seike T, Abe Y, Takaku M.

Pencil-core granuloma of the face: report of two rare cases. J Plast

Reconstr Aesthet Surg 2011;64:1235-1237.

4. Kim YJ, Ahn JY, Kim BJ, Kim MN, Song KY. A case of graphite foreign

body misdiagnosed as blue nevus. Ann Dermatol 2007;19:166-169.

5. Jeong GJ, Kim JM, Li K. A case of graphite granuloma mimicking

melanoma. Korean J Dermatol 2019;57:281-282.

Table 1. Case reports of pencil-core granuloma in the Korean literature

CaseSex/age

(yr)Lesion site

Lag period

(yr)Size (cm)

Jeong et al.5 Female/39 Left heel 20 2×2

Kim et al.4 Female/19 Right hand 10 0.5×0.3

Our case Female/62 Left nasolabial fold 50 1.0×0.5

Fig. 1. (A) A well-defined 1.0 cm×0.5 cm-sized skin-colored to bluish subcutaneous nodule on the left na-solabial fold (arrow). (B) The pencil lead, which measured about 0.8 cm in length, with black pigmented sub-cutaneous tissues. (C) Granulomatous inflammation with dispersed black pigments and fibrosis in the dermis (H&E, ×10). (D) Granulomas com-posed of histiocytes, foreign body giant cells, and black pigments (H&E, ×400).

AA BB

CC DD