Cyst Removal in Singapore by a Plastic Surgeon - Histology, POCUS and Scarring
When I was in training, a senior surgeon passed down a rule of thumb for unusual presentations:
"When there's pus, always think about sending tissue for histology"
At the time, that felt counter-intuitive and very kiasu to me. In everyday practice, pus is the universal calling card of an acute, benign inflammatory response: bacteria, dead cells, a blocked pore, or an infected cyst. Cancer or complex chronic diseases, by contrast, are supposed to look different.
Yet biological tissue rarely follows the textbooks. Whether on the face or anywhere else on the body, a discharging lump is not always a simple cyst. Three recent cases from my practice illustrate why treating such "cysts" requires more than blind excision, how point-of-care ultrasound (POCUS) transforms surgical precision, and why skipping pathology is a risk no patient should ever take.
Case 1: Classic Epidermal Cyst
This patient came with a lump over the left temple. He noted that it had been gradually increasing in size, with recent episodes of bloody discharge mixed with cheese like material. On examination, the presentation was classic: a firm lump with an obvious central punctum tethered to the overlying skin.
A central punctum is the hallmark of an epidermal cyst, representing the plugged follicular opening from which the cyst originally formed. When a cyst expands rapidly or becomes inflamed, micro-vessels in the stretched cyst wall can rupture, mixing blood with trapped keratin and sebum to produce bloody, foul-smelling discharge.
For this patient, the treatment was a direct elliptical excision under local anaesthesia (see above). By including the punctum and overlying skin ellipse within the excision, the entire cyst wall was delivered intact without rupture and confirmed on final histology from the laboratory. The incision was aligned and closed precisely along the relaxed skin tension lines to minimise scarring. Straightforward, definitive, and healed as a fine line that was barely visible.
Case 2: Resolved Armpit "Cyst", POCUS Mapping, and Early Hidradenitis
Lumps outside the face carry their own distinct anatomical and diagnostic traps.
A patient presented with an acutely red and painful armpit "cyst", associated with surrounding induration (tissue hardening). She was given a trial of antibiotics, failing which she would have required surgical drainage. Fortunately, she responded well and over three weeks, the pain resolved, the swelling flattened, and the surrounding inflammation settled.
At her review, the patient asked a very sensible question, "since the lump has gone, is surgery still necessary?" In my opinion, this is actually the best time to do it. Antibiotics address the infection, but they do not treat the root of the problem. Her main concern, understandably, was scarring especially as she has had multiple cysts in other parts of the body removed previously by various surgeons with variable results.
Rather than guessing by palpation, I utilised point-of-care ultrasound (POCUS) in the examination room. Even when flattened clinically, POCUS clearly demonstrated a well-defined hypoechoic (dark) area with a hint of a cyst wall beneath the epidermis (see below). This enabled me to map the location and depth of what was presumed to be a previously infected "cyst".
With zero blind dissection, the "cyst" was excised as an ellipse and confirmed on histology to measure 1.5 cm by 0.5 cm, with the underlying subcutaneous tissue at 1.2 cm thick, meaning the "cyst" itself was approximately 0.3 cm thick. This is in keeping with the POCUS image above (see the scale on the left, which are in increments of 10 mm).
The histology however, returned with an important surprise. It reported features compatible with an early inflammatory process, and the possibility of hidradenitis suppurativa could not be completely excluded. With this information, her history started to make more sense now as she has had multiple "cysts" affecting the lower abdomen and chest i.e. the inter-triginous areas.
Case 3: A Cheek "Cyst" That Was Actually Skin Cancer
The most deceptive case presented as a solitary cheek "cyst" in the lower cheek.
Due to its prominent location, the patient was rightly concerned about scarring with removal. She had initially consulted a Dermatologist, who diagnosed that the lump was likely a cyst as what was presumed to be hair follicles were seen and embedded within.
However, given the patient's aesthetic concerns, she was advised to see a Plastic Surgeon. On review, there was nothing that stood out to suggest anything sinister:
A history of prior swelling and spontaneous pus discharge.
Embedded hair follicles visible directly over the surface of the lump (see above).
A subcutaneous firm consistency typical of an inflamed follicular lesion.
The patient wanted it removed with minimal fuss and was not so keen when I explained that every excised specimen should be sent for formal histological evaluation. To her, the laboratory fee felt like an unnecessary add-on for an "obvious" cyst.
I held firm. Skipping histology in my specialist practice is non-negotiable. I explained that it may very well be nothing, but think of it as buying peace of mind. To this, she agreed. A 5 mm punch excision was performed, the "cyst" was sent off to the laboratory and the wound was closed along her natural relaxed skin tension lines.
A week later, the report came back as nodular type basal cell carcinoma (BCC). The BCC measured 2 mm wide and 1.2 mm thick. Deep margins were clear by 1.2 mm but the closest lateral margin was only 0.1 mm clear. She was counselled on the need for further surgery to achieve clear oncological margins as per international guidelines to reduce the risk of recurrence.
How does a skin cancer present with pus and embedded hair follicles? Two potential mechanisms explain this camouflage:
Secondarily Infected, Ulcerated Tumour: As a BCC grows, its fragile, disorganised neo-vasculature outgrows its blood supply, causing focal central necrosis and ulceration. Once the skin barrier breaks down, surface bacteria invade, producing true pus discharge that masks the cancer beneath.
The Collision Lesion: On sun-exposed skin, an inflamed hair follicle or genuine small cyst can physically collide with an early, unsuspected BCC sitting right beside it.
Had this lump been lasered off without sending off for evaluation (as I have explained previously about treatment of moles), the diagnosis would have been missed entirely. The malignancy would have continued to grow, deep down, and unchecked. This is a point I have mentioned as well, that skin cancer in Singapore is most likely under-diagnosed.
The Financial Reality: Why Histology Protects Your Insurance Claim
A major reason patients hesitate over pathology or specialist consultation is the fear of unpredictable, out-of-pocket bills. This hesitation often stems from a misunderstanding of how medical insurance operates in Singapore:
Insurers require objective proof: Private health insurance strictly excludes elective cosmetic treatments. Insurers do not approve claims based on an aesthetic invoice alone; they require a specialist's written report documenting a medically necessary condition (such as an infected/ruptured cyst, hidradenitis, or skin cancer). Without histology, an insurer may deem the excision medically unnecessary, leaving one to pay entirely out of pocket.
Billing within TOSP benchmarks: When an excision is medically indicated, properly documented, and billed transparently within the Ministry of Health's Table of Surgical Procedures (TOSP) fee benchmarks, insurance works as intended.
What happens in real life: In my practice, patients presenting with genuine, symptomatic or infected lumps regularly receive coverage up to the maximum allowed with their respective policies. Depending on circumstances, some are treated under a pre-approved Letter of Guarantee (LOG), such as the axillary case described above. Others pay cash upfront, and then apply for reimbursement once the diagnosis is established, such as the cheek case that came back as skin cancer, and treatment completed.
This is why specialist treatment comes at a specialist fee; and that is also precisely why medical insurance exists - to protect you financially when there are real, verifiable medical diagnoses, supported by objective proof through histology.
For patients considering lump or cyst removal on the face, hands or body, you can read more about my approach to Same Day Surgery and Skin Cancer.
Written by Dr Ng Zhi Yang, UK & Singapore accredited Plastic Surgeon
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