Nodular Basal Cell Carcinoma

01Arborizing telangiectasias are the dermoscopic hallmark of nodular BCC. The defining vessels are sharp, bright red, large-stem trunks that branch progressively into finer terminal capillaries, all in focus across the lesion. They reflect dilated neovascular tumor vessels in the superficial dermis. In Reiter's pooled analysis of 1503 nodular BCCs the prevalence was 75 percent, compared with 21 percent in superficial BCC. Out-of-focus or interrupted vessels argue against nodular BCC.

02Large blue-grey ovoid nests are the dominant pigmented feature of nodular BCC, present in 36 percent of cases overall and up to 54 percent in pigmented variants. Histologically they correspond to large well-defined basaloid tumor nests with melanin aggregates that invade the dermis. In Lallas' multivariate analysis their presence reduced the odds of superficial BCC roughly 12-fold and 22-fold in flat-appearing lesions. Detection of even a single ovoid nest should redirect management toward excision rather than topical therapy.

03Central ulceration is the second most frequent feature of nonpigmented nodular BCC and appears in 31 percent of nodular cases overall. It presents as a structureless red to black-red area, often covered by a hematogenous crust. When ulceration is large and the surrounding skin shows arborizing vessels and ovoid nests, the diagnosis is essentially confirmed.

04Other features that support nodular BCC include shiny white structures (43 percent), multiple blue-grey globules (26 percent), and clefting visible on RCM. Maple leaf-like areas, spoke-wheel structures, and concentric structures are uncommon (3 to 6 percent each) and should raise suspicion for a mixed or superficial component instead.

05Reflectance confocal microscopy of nodular BCC reveals large, well-circumscribed bright tumor islands with peripheral palisading of basaloid cells and dark peritumoral clefting. In Longo's 2014 series, big tumor islands were present in 73 percent and peripheral palisading in 91 percent of nodular tumors. Clefting was present in 77 percent and was the strongest independent RCM predictor of nodular versus other subtypes (17-fold higher odds).

06Depth correlation matters for treatment planning. Nodular BCC extends into the reticular dermis but typically does not infiltrate beyond, allowing standard excision with 4 mm margins to clear most low-risk lesions. The NCCN designates nodular BCC as a low-risk histology, but anatomic site, size, immunosuppression, and recurrence move many lesions into the high-risk category that mandates Mohs.

07Mohs micrographic surgery is the treatment of choice for nodular BCC with any high-risk feature: location in the H zone of the face (central face, nose, eyelids, lips, ears), size 1 cm or larger on the M zone or 2 cm or larger on the L zone, poorly defined borders, recurrent disease, immunosuppression, prior radiation, or aggressive growth on biopsy. Five-year recurrence rates are 1 percent for primary and 5.6 percent for recurrent nodular BCC with Mohs, versus 10 percent and 17 percent with standard excision.