Dermoscopy of penile sclerosing granuloma

Abstract

Penile sclerosing granuloma is a foreign body reaction to the injection of material, usually for genital augmentation purposes. Patients commonly deny having had or performed these procedures on themselves, and diagnosis can be challenging. We describe the case of a 62-year-old man with a 10-year history of a growth on the penile shaft. Dermoscopic examination showed an orange background with shiny white structures, suggesting a granulomatous pathology. Guided biopsies confirmed a sclerosing lipogranuloma. The patient admitted to having self-injected motor oil. For the first time, we report the dermoscopic description of sclerosing granuloma, which will improve clinical diagnostic precision and guide biopsies. We also contribute the first description of a dermoscopic rainbow pattern in a granulomatous disorder; this could be due to a physical phenomenon called ‘dichroism’.

BACKGROUND

Penile sclerosing granuloma (PSG) is defined as a foreign body reaction due to lipids (lipogranuloma/oleogranuloma), hydrocarbons (paraffinoma), silicone (siliconoma), methacrylates, hyaluronic acid or collagen fillers, mainly injected in pursuit of genital augmentation.¹

Patients commonly deny having had or performed any genital procedures, sometimes subjecting themselves to invasive studies (something previously described in the literature), and diagnosis becomes a clinical challenge.² To our knowledge, we describe for the first time (in English literature) dermoscopic images of sclerosing lipogranuloma.

Case presentation

A 62-year-old man presented to our Male Genital Dermatology Unit. He was previously seen in the emergency department due to minor unrelated trauma. After a complete physical examination, he was hospitalised by our urology colleagues due to a possible penile tumour. He had a 10-year history of a growth on the penile shaft (figure 1A). The patient had sexual dysfunction, the lesion was otherwise asymptomatic, and he repeatedly denied any local procedures. We used MRI to define tumorous extension. Imaging showed a tumorous mass limited to dermal and hypodermal tissues. Buck’s fascia (which defines the skin limits) was uncompromised (figure 2). Two skin biopsies were performed from the same sites as the dermoscopic photographs (figure 1B, C) and confirmed the diagnosis of a PSG (figure 3A, B). The patient later admitted he had self-injected motor oil and declined any kind of treatment.

Figure 1.

Clinical image and zone of dermoscopic photographs. (A) Penile augmentation in penile shaft and base; (B) and (C) selected zones for dermoscopic photographs. In zone (B) under dermoscopy (magnification, 20×), a rainbow pattern (black oval) characterised by white dots (blue arrows), violaceous zones marked with asterisks (*), shiny white structures (yellow arrow) and shiny white clods (black dotted circle) are found, with a general orange structureless background (black arrows). A few linear and branched vessels are seen scattered and randomly distributed throughout the lesion (red arrows). In zone (C) under dermoscopy (magnification, 20×), large shiny white clods are found randomly distributed in the lesion (green arrows). A rainbow-like pattern is seen (yellow dotted oval) characterised by white dots (pink arrows) and a violaceous background (light blue arrow).

Figure 2.

MRI image of the penis (prebiopsy). There is a dermal and subcutaneous diffuse thickening in the penile shaft (blue arrows), with ill-defined margins. It had a hypointense signal on T1 and T2 sequences. Buck’s fascia (red arrows), corpus cavernosum (green arrows), corpus spongiosum and glans penis (pink arrows) did not show any radiological signs of compromise. No lymph node involvement was noted.

Figure 3.

Histology. (A) Biopsy of the dermoscopic zone demarcated in figure 1B, showing superficial granulomas (*) surrounding the lipid micella (black arrows), consisting mainly of histocytes and lymphocytes. (B) Biopsy of the clinical zone demarcated in figure 1C, showing acanthosis (yellow arrows), dense fibrosis (green arrows) and deeper granulomas (*) surrounding the lipid micella (black arrows).

Discussion

PSG must be considered in the differential diagnosis of chronic penile tumours. The absence of an epidermal component (eg, no scale, erosion or ulceration), with significant tumorous involvement of the subcutaneous tissue, points towards a subepidermal skin disorder.

Dermoscopy involves analysing images using a handheld dermatoscope that can be coupled with a camera (such as a smartphone). We used dermoscopic examination as a diagnostic tool. This non-invasive handheld method can serve as a complementary physical examination tool, revealing clinical signs that are not visible to the naked eye, and helps select biopsy sites.

A thorough literature search has allowed us to compare the dermoscopic findings in granulomatous diseases with their histopathological correlates. Structureless orange zones, shiny white streaks, shiny white blotches, white dots, and linear and branched vessels have all been already described in granulomatous diseases, including our case (table 1). Herein, we add for the first time the rainbow-like pattern.

Table 1.

Dermoscopic findings relevant to our case and other granulomatous disorders

Descriptive terminology	Metaphoric terminology	Definition21	Probable histopathological correlation	Granulomatous disorders
Perpendicular white lines	Shiny white streaks	Short white lines oriented perpendicular (orthogonal) and parallel to each other*	Polarisation of thickened hyaline fibrous bundles in the dermis3 5 6 22 23	FBG4 GA6 22 CL23–25 Leprosy26 LV27 NL28 Sarcoidosis29
Shiny white clods	Shiny white blotches and strands	White structures (circles, ovals or large structureless areas) longer and less well-defined than streaks. They may be distributed in parallel, oriented haphazardly or form blotches (clods)*	Collagen degeneration in the dermis, acanthosis or wedge-shaped hypergranulosis.6 7 22 30 31	Actinomycetoma32 Blastomycosis33 CG34 CBM35 Cryptococcosis31 EM36 37 GA6 22 29 CL23–25 38–41 LV27 NL28 PNGD30 Sarcoidosis42–45 Sporotrichosis46
White dots	Irregular granules	Similar to white clods, but usually smaller than the diameter of a terminal hair*		CL4 23–25 Leprosy47 48 LV27 Sarcoidosis44 45
Polychromatic structureless zone	Rainbow pattern	Circumscribed structureless area displaying the whole spectrum of the visible light spectrum*	Interplay between polarised light absorption, diffraction and diffusion, exclusively in palpable lesions, possibly due to the presence of: ‘Dichroism’: local variations in refractive index due to changes in direction and composition of structures with birefringence potential (eg, collagen) in a disorganised dermis8–11 ‘Diffraction grating’: closely arranged ‘back-to-back’ vessels, with minimal intervening tissue (slits)10 12–15 Intracellular and extracellular abundant eosinophilic hyaline globules16 17 Bundles of spindle cells surrounding irregularly shaped vessels9 16
Structureless orange zones	Homogeneous orange pattern	Orange area where the terms ‘lines’, ‘dots’, ‘clods’, ‘circles’ and ‘pseudopods’ are missing.	Dense and compact granulomatous inflammatory infiltrate and/or lipid deposits in the dermis.3 4 18 22 24 26 30 31 49–54	AOX55 AEGCG52 Blastomycosis33 CG34 CBM35 56 57 FBG4 FTG58 GA22 49 59 GPD54 GPPD60 GR61 IFAG62 CL24 38 41 51 63 Leprosy26 47 48 LMDF64 65 LV4 27 61 NL28 44 49 50 59 PNGD30 Sarcoidosis4 29 42–45 61 66 Sporotrichosis46
Linear vessels	Linear vessels (regular)	Linear (or mildly curved), short and thin (regular)	Increased and dilated vessels in papillary dermis3 26 28	AOX55 Blastomycosis67 Cryptococcosis31 GA22 49 59 GR68 IFAG62 69 CL23–25 38 41 51 Leprosy36 47 LMDF64 LV4 27 61 NL29 44 PNGD30 RN29 Sarcoidosis4 29 42–45 61 UG68
Branched vessels	Arborising vessels	Well-focused, thick and dividing into smaller vessels	Atrophic changes reveal deeper, thicker telangiectatic blood vessels from the reticular dermis. These are also increased in number and dilated, and their walls may be thickened (endothelial swelling)3 28 30 44 49 50	AOX55 Cryptococcosis31 GA22 59 Histoplasmosis70 CL24 25 38 41 51 63 Leprosy26 47 48 LMDF61 LV61 NL28 29 44 49 50 59 PNGD30 RN29 Sarcoidosis45 61 Sporotrichosis46 UG71

*Seen only under polarised dermoscopy

AEGCG, annular elastolytic giant cell granuloma; AOX, adult-onset xanthogranuloma; CBM, chromoblastomycosis; CG, candidal granuloma; CL, cutaneous leishmaniasis; EM, eumycotic mycetoma; FBG, foreign body granuloma; FTG, fish tank granuloma; GA, granuloma annulare; GPD, Granulomatous periorificial dermatitis; GPPD, granulomatous pigmented purpuric dermatosis; GR, granulomatous rosacea; IFAG, idiopathic facial aseptic granuloma; LMDF, lupus miliaris disseminatus faciei; LV, lupus vulgaris; NL, necrobiosis lipoidica; PNGD, palisaded neutrophilic and granulomatous dermatitis; RN, rheumatoid nodules; UG, umbilical granuloma.

Orange colour has been widely described as a dermoscopic hallmark of granulomatous disorders.^{3 4} This colour has been found in 80.7% (21/26) of previous reports describing dermoscopy of distinct granulomatous dermatoses, with the exceptions being rheumatoid nodules, umbilical granuloma, cryptococcosis, histoplasmosis and actinomycetoma. In our case, we found this colour randomly distributed across the entire lesion. In certain areas, it was not found due to a deeper infiltrate and an overlying acanthotic epidermis (figure 3B).

Another important dermoscopic finding in granulomatous disorders are shiny white structures.⁵ The significant fibrotic process due to chronic inflammation in PSG leads to large areas with shiny white structures, which represent fibrous bundles in the dermis (figures 1C and 3B).^{6 7}

The dermatoscopic rainbow pattern has been associated with a wide range of tumorous and inflammatory lesions.^8–18 The sign was first published in 2009 by Hu et al¹² in Kaposi’s sarcoma and described as ‘various colours in the rainbow spectrum’. However, lately, it has been described with only three colours.^{8 12–14} Although the histopathological correlation of this dermoscopic finding is still under debate, it is possible that it may not be due to a single phenomenon. Histology did not show any significant vascular pathology. We believe that this iridescent appearance is due to ‘dichroism’, produced by the interaction of polarised light with local structures, such as collagen and lipids, which have variations in their refractive index, generating changes in the reflected light that is transmitted in different wavelengths, and thus perceived as different colours (figures 1B and 2A).^8–11 The number and types of colours are not especially relevant; it is their interpretation as an underlying physical phenomenon in a dermis with a dense inflammatory infiltrate that is important. The degree and depth of inflammation are probably the cause of few or many colours. Future studies are needed to clarify these concepts.

Dermoscopy has been increasingly used in genital dermatology, mainly for tumorous and infectious disorders.^{19 20} Herein, we describe the dermoscopic signs of sclerosing granuloma of the penis for the first time. We have shown that dermoscopy enhances clinical diagnosis and optimises biopsy site selection.

Learning points.

• Penile sclerosing granuloma (PSG) must be considered in the differential diagnosis of chronic penile tumours.

• Dermoscopy can assist in the diagnosis of PSG, particularly in patients who deny such procedures, with orange colour (granulomas), shiny white structures (fibrosis) and a novel description of the rainbow pattern (fibrosis around lipid micella).

• Dermoscopy can guide biopsy site selection.