Painful Gluteal Lesion

A 54-year-old male patient came with chief complaint of a tender lesion on his left gluteal region since one year [Figure 1]. On cutaneous examination, a single, well-defined skin-colored nodule of size 1 × 1 cm was present over the lower left quadrant of left gluteal region. Pinpoint tenderness was present on gentle pressure over the firm lesion. Histopathological examination of the excised specimen showed a dermis with varying-sized vessels lined by endothelial cells surrounded by glomus cells [Figure 2a and b]. Borders of the lesion were not well defined, and cells were arranged in diffuse sheets and nests without any pleomorphism. Immunohistochemistry revealed CD34 and smooth muscle actin positivity [Figure 3a and b]. Follow-up examination revealed no signs of recurrence.

Figure 1.

Well-defined, skin colored nodule approximately 1 × 1 cm in size seen over the left gluteal region

Figure 2.

(a) Dermis composed of varying-sized vessels lined by endothelial cells surrounded by. Cells are arranged in diffuse sheets and nests. (Hematoxylin and eosin stain—40×); (b) Monomorphic, medium-sized cells with basophilic nuclei (glomus cells) (Hematoxylin and eosin stain – 100×)

Figure 3.

(a) Positive for CD34 on immunohistochemistry; (b) Strongly positive for smooth muscle actin on immunohistochemistry

Diagnosis?

Glomangioma

Discussion

The initial description of glomus tumor, as a painful subcutaneous nodule was given by Wood in 1812.[1] Glomus tumors are benign vascular tumors originating from the modified smooth muscle cells of the glomus body.[2] Glomus bodies present in the reticular dermis are neuromyoarterial receptors comprising an afferent arteriole, an arteriovenous anastomotic Suquet-Hoyer canal, an efferent venule, intraglomerular reticulum with its capsule.[1]

Glomus body can affect blood pressure and thermoregulation by alternating cutaneous blood flow, which results in cold sensitivity. Glomus tumors can present either as benign or rarely malignant, single or rarely multiple, digital or extradigital. The prevalence of extradigital glomus tumors is estimated to be 2%.[3] The clinical triad for diagnosis includes tender nodules, cold sensitivity, and pinpoint pain on pressure.

Subungual types are more common as glomus bodies are seen in abundance which explains the rarity of extradigital glomus tumors. However, 60% of extradigital glomus tumors are seen on the upper extremity and 24% on the trunk.[1] Atypical or ectopic variants of glomus tumors can also occur in visceral organs where glomus bodies do not exist.[4]

Pathogenesis of the glomus tumor is not clear. Subungual are more common in younger women, whereas extradigital are common in old-aged men. Multiple tumors can be inherited (Autosomal dominant [AD]) in globulin gene on chromosome 1p21-22 and seen at birth or early infancy.[3]

World Health Organisation has classified glomus tumors into three types, benign, intermediate glomangiomatosis (diffuse glomus tumor), and malignant (glomangiosarcoma).[3] They are typically composed of glomus cells, vasculature, and smooth muscles by which they are subcategorized as solid variant (predominant glomus cells, poor vasculature, and scant smooth muscle component), glomangioma or vascular variant (prominent vasculature), and glomangiomyoma or myxoid variant (prominent vasculature and smooth muscle components).[5] The clinico-demographic differences between subungual and extradigital glomus are explained in Table 1.

Table 1.

Clinico-demographic differences between subungual and extradigital glomus tumor

Characteristics	subungual glomus tumor	Extradigital glomus tumor
Nomenclature	Digital glomus tumor	Slledsdivesn glomus tumor
Incidence	66–75%	25–34%
Gender	F>M	M>F
Age (years)	30–50	40–60
Site	subungual nail bed	Extremities and trunk
Size	Smaller<10 mm	>10 mm
Tenderness	Present	Present
Cold sensitivity	Present	+/-
Color	Bluish or reddish	Blue, Purple, reddish-blue, reddish-purple

Clinically other painful cutaneous tumors are known by the acronym BLEND AN EGG (Blue nevus, leiomyoma, eccrine spiradenoma, neurilemmoma, dermatofibroma, angiolipoma, neuroma, endometrioma, granular cell tumor, and glomangioma). Histopathological examination of glomus tumor consists of rounded cells with well-demarcated cell membranes arranged in a perivascular growth pattern. Histopathological differential diagnosis includes vascular and smooth muscle tumors such as myopericytoma, myofibromatosis, epitheloid angiomyolipoma, and hemangioma.[6] The differentiating points of close mimickers of glomus tumors are tabulated in Table 2.

Table 2.

The differentiating points of close mimickers of glomus tumors are tabulated

Characteristic	Extra digital Glomangioma	Dermatofibroma (benign fibrous histiocytoma)	Eccrine spiradenoma	Leiomyoma cutis
Site	Extremities and trunk	Legs	Head, neck, trunk	Nipple, scrotum, vulva
Gender	M>F	F>M	M=F	M=F
Age (years)	40-70	Any age	15-35	Adults
Symptoms	Blue or bluish-purple colored nodule, Pinpoint tenderness, cold sensitivity	Painful hyperpigmented nodule with dimple sign	Painful, blue-colored, small, nondescript lesions	Solitary or grouped, red, pink, purple, or brown waxy or translucent nodules
Pathogenesis of pain	Modified smooth muscle cells	Entrapped collagen bundles in between intercalating strands of fibroblasts	Disorganized nerve fibers	Involuntary smooth muscles
Dermoscopy	Homogeneous, unstructured purplish area is surrounded by a whitish region.	Central white scar-like patch and peripheral delicate pigment network.	Pink, orange background, peripheral yellowish globules, blue-grey ovoid nests.	Central hypopigmented area with peripheral delicate hyperpigmentation and arceiform areas with ectatic vessels
Histopathology	Branching vascular channels are separated by connective tissue stroma containing aggregates, nests, and masses of glomus cells.	Acanthosis with pseudoepitheliomatous hyperplasia and grenz zone. Whorled fascicles of spindle cell proliferation with collagen deposition.	Deeply basophilic, sharply marginated lobules lying freely in the dermis. blue cells	Interlacing bundles of smooth muscle bundles with eel-shaped nuclei.
IHC	CD34, SMA	CD68, HAM56, XIIIa - positive CD34, SMA - Negative	CK5/CK6, S100 - positive SMA - Negative	SMA
Treatment	Excision	Excision	Excision	Excision

Dermoscopic examination of glomus tumor shows structureless homogenous purpilish area surrounded by a whitish region and intensely purplish lagoons surrounded by a pale halo.[6] With only 20% of initial correct diagnosis with extradigital glomus tumor (EGT), due to the unusual locations, dermoscopy plays a pivotal role in non-invasive diagnosis of EGT.[7]

Glomus tumors are benign, but extradigital glomus tumors have a 1% risk of malignancy involving oesophagus, thyroid, heart, lung, and intestine.[1] Ultrasound can be done to assess the size and to locate. Doppler and MRI can be done to assess the blood flow and confirm the diagnosis, respectively.[1] Diagnosis can be complemented by pertinent tests such as Love test (excruciating pain upon palpation, as was evident in our case) and Hildreths test (decrease in the pain on applying proximal tourniquet).

Difficulty in diagnosing the extradigital glomus tumor is due to the absence of clinical triad in extradigital tumors. For both digital and extradigital complete excision is the definitive treatment.[8] Incomplete excision results in early recurrence of pain. Late recurrence of pain after 2–3 years is due to new lesion. Recurrence rate in glomus tumors ranges from 12% to 33%.[1]

Conclusion

Clinicians need to consider glomus tumor in the differential diagnosis of extradigital painful lesions. Rapid diagnoses with aid of clinical triad, immunohistochemistry, and MRI in doubtful cases can help to avoid chronic pain and delayed diagnoses.

Learning points

1. Consider glomangioma if tender nodules, cold sensitivity, and pinpoint pain on pressure are present.

2. Ultrasound, Doppler, and MRI can be utilized for assessing the size, blood flow, and confirming the diagnosis of glomus tumors, respectively.

3. Complete excision of the lesion is useful for diagnosis, treatment and to prevent the recurrence.

4. Incomplete excision results in early recurrence of pain and late recurrence of pain after 2-3 years are due to new lesion.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.