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Preferred biopsy technique according to pathology

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Before reading: This article is intended exclusively for healthcare professionals (physicians, residents, and other professionals with medical training). The content is for educational and academic updating purposes and does not replace individual clinical assessment, professional judgment, or specialized medical consultation . Diagnostic and therapeutic decisions should always be made within the context of each individual patient and under the responsibility of the treating physician.

The information presented is based on concepts widely described in current scientific literature, clinical guidelines, and articles published in specialized medical journals . However, medicine is a constantly evolving field , so the content presented here should not be interpreted as absolute truth or a universal recommendation applicable to all cases . The reader should consider this information as a general guideline and is always advised to review the original sources cited , as well as the most recent available evidence, before making specific clinical decisions.

Key messages

  • A “correct” biopsy is defined by which layer should be included (epidermis, reticular dermis, hypodermis) and by which study is required (H&E, IFD*, microbiology), rather than by operator preference. Elston 2016

  • In vasculitis and autoimmune bullous diseases, diagnostic yield is critically dependent on site and time , and usually requires two biopsies (H&E + IFD). Alpsoy 2022 Mahmood 2024

  • In panniculitis, a sample lacking sufficient hypodermis limits histological classification and delays diagnosis; therefore, deep biopsies (incisional/excisional or deep punch biopsy, depending on the case) are preferred. Tomasini 2013 Peters 1989

  • In alopecia, performance increases when two properly oriented punches are obtained and vertical and transverse cuts are combined according to the scenario. Elston 1995 Palo 2018

  • In cases of suspected melanoma, the gold standard recommendation is an excisional biopsy with narrow margins to allow for microstaging; when using a deep shave biopsy, there is a significant risk of a positive deep margin, impacting restaging in a minority of cases. (Swetter 2019, Ahmadi 2021)

*IFD: Direct Immunofluorescence

Indications and patient selection

  • The indication for biopsy is strongest when the diagnosis will alter management (oncological staging, need for immunosuppression, suspicion of deep infection or systemic vasculitis), and it should be planned to answer a diagnostic question explicitly stated in the request. Elston 2016

  • Site selection should prioritize active and representative lesions , avoiding intensely excoriated/ulcerated areas if the goal is to assess architecture, and avoiding sampling exclusively "end-of-path" areas (e.g., central scarring in cicatricial alopecia). Elston 2016 Pinedo-Moraleda 2023

  • When special studies are anticipated, the logistics (transport method, timing, sample fractionation) must be defined before taking the biopsy, because inadequate fixatives can invalidate IFD or other tests. Mahmood 2024 Vodegel 2004

Technique/protocol (by clinicopathological pattern)

1) Pigmented lesions / suspicion of melanoma

  • Preferred technique: narrow-margin excisional biopsy encompassing the entire width of the lesion and sufficient depth for Breslow thickness. Swetter 2019

  • If the lesion is large or located where complete excision is impractical, a selected partial biopsy (incisional/punch/deep shave) may be considered, understanding the risk of underestimation due to transection or unrepresentative sampling. Elston 2016 Ahmadi 2021

  • Evidence on shave in melanoma: In a meta-analysis, approximately 42.9% reported a positive deep margin after shave and approximately 7.7% changed stage after definitive resection, with significant heterogeneity between studies. Ahmadi 2021

2) Cutaneous squamous cell/epidermoid carcinoma and other suspicious keratinocytic lesions

  • There is no single “optimal” technique for squamous cell carcinoma (SCC); punch, shave/tangential, and excisional techniques are all acceptable, provided the sample is of adequate depth to assess invasion and high-risk features when applicable. Alam 2018

  • A common error is a sample that is too superficial, preventing the assessment of invasion or tumor architecture relevant to management. Elston 2016

3) Basal cell carcinoma (subtyping and correlation with definitive specimen)

  • For histological subtyping of BCC, an accuracy of approximately 80% has been described for both shave and punch biopsies in comparative series, so both techniques may be reasonable depending on morphology and site. Russell 1999

  • When behavior depends on recognizing more aggressive or infiltrative patterns, sample adequacy and representativeness remain the main limiting factor. Elston 2016

4) “Superficial” inflammatory dermatoses (psoriasiform, eczema, lichenoid, drug reactions)

  • In inflammatory eruptions, the standard operating procedure is usually a punch of sufficient size to observe architecture (frequently 4 mm), adjusting the size if granulomatous patterns or subtle changes that are missed in small cores are suspected. Nischal 2008 Elston 2016

  • Site selection (active, non-excoriated lesion, “evolving” border) is as important as technique, because many dermatoses share nonspecific end patterns. Elston 2016

5) Cutaneous vasculitis (including small vessel vasculitis)

  • Two biopsies are recommended : one for conventional histology and one for direct immunofluorescence (DIF), because vasculitis is dynamic and immune deposits can degrade over time. Alpsoy 2022

  • The yield increases when biopsies are taken early (typically within 24–48 hours of lesion onset), and a sample reaching the subcutis should be ensured (deep punch or excisional). Alpsoy 2022 Azanza 2020

  • To maximize information, it is suggested to identify the appropriate lesion site for H&E staining (e.g., purpuric papule) and the optimal site for DIF staining (e.g., blanchable erythematous macule), understanding that a negative DIF does not exclude vasculitis and requires correlation. Alpsoy 2022

6) Autoimmune blistering diseases and other indications for IFD (pemphigoid, pemphigus, dermatitis herpetiformis, etc.)

  • In cases of suspected autoimmune blistering disease, a biopsy for direct immunofluorescence (DIF) of perilesional skin (adjacent to the blister) is recommended, along with a second biopsy of a suitable lesion for hematoxylin and eosin (H&E) staining, avoiding taking DIF from frank erosion. Mahmood 2024, Elston 2016

  • The sample for direct immunofluorescence (DIF) requires specific handling and an appropriate transport medium; Michel's medium is a classic option described for preserving tissue immunoreactants. Jones 1995 Mahmood 2024

  • In transport for direct immunofluorescence (DIF), alternatives such as saline solution have been compared for limited periods in certain diagnostic scenarios, illustrating that pre-analytical procedures can modify signal-to-background ratio and performance. In these cases, sample collection and shipment to the laboratory for processing must be coordinated in advance. (Vodegel 2004)

7) Panniculitis (erythema nodosum and differentials, lupus panniculitis, SPTCL**, etc.)

  • The rule of thumb is “no hypodermis, no panniculitis”: the biopsy should include sufficient subcutaneous fat to classify septal versus lobular panniculitis and assess for associated vasculitis. Tomasini 2013

  • In lupus panniculitis, deep excisional biopsy has been recommended for diagnosis, precisely because of the need for adequate subcutaneous tissue. Peters 1989

  • The choice between incisional/excisional vs. deep punch is determined by size and site, but the non-negotiable criterion is the effective depth and representativeness of the active lesion. Tomasini 2013 Elston 2016

** SPTCL: Subcutaneous Panniculitis Like T Cell Lymphoma

8) Alopecia (non-scarring vs scarring)

  • Obtaining two scalp punches, correctly oriented and deep enough to include the bulb/superficial hypodermis, is favored because combining cuts improves performance. Elston 1995 Pinedo-Moraleda 2023

  • The combination of vertical and cross-sectional imaging surpasses either technique alone in overall diagnostic performance and should therefore be requested and planned with the laboratory. Elston 1995 Palo 2018

  • The biopsy should be taken from the active border in cicatricial alopecias (where inflammation is still present) and not from the completely scarred center if the objective is etiological. Pinedo-Moraleda 2023

9) Nail unit (tumors, longitudinal melanonychia, inflammatory dystrophies, onychomycosis when applicable)

  • Nail biopsy is defined by the target compartment (matrix, bed, folds, lamina), because most lamina changes reflect matrix pathology. Grover 2018

  • In longitudinal melanonychia with clinical suspicion, sampling is usually directed at the matrix (origin of the band), using techniques that minimize dystrophy but allow for adequate histology, recognizing that the primary objective is to exclude melanoma. (Rich 1992, Grover 2018)

  • For onychomycosis, there are less invasive sampling strategies than skin biopsy, but when a biopsy is chosen, the objective (H&E with PAS or others) must be specified to the laboratory, because its usefulness depends on the processing. Grover 2018

10) Cutaneous lymphomas and “mimickers” (MF/SS, CBCL***) and “random” biopsies in IVLBCL***

  • In cases of suspected mycosis fungoides/syndrome, multiple skin biopsies/mapping (e.g., punch biopsies ≥4 mm) of the most indurated/representative areas are recommended because early histology can be subtle and clinicopathological correlation is essential. Lee 2023, Elston 2016

  • In cases of IVLBCL with clinical suspicion and skin without specific lesions, “random” skin biopsy has been proposed, and better performance has been described with incisional approaches (not superficial punch biopsy), which again underscores the role of depth and the subcutaneous vascular bed. Enzan 2019

***CBCL: Cuteaneous B Cell Lymphoma / IVLBCL: Intravascular Large B Cell Lymphoma)

11) Infections (especially subcutaneous/deep mycoses) and need for histology

  • In fungal infections with subcutaneous or atypical presentations, biopsy provides information on architecture, inflammation, and visualization of microorganisms using special stains, and can guide diagnosis even if culture fails; therefore, the sample must be appropriate to the affected area. Howell 2023

  • When infection is suspected, the diagnostic value depends on coordinating histology and, when applicable, microbiology, ensuring that pre-analytical findings do not invalidate the purpose of the sample. Elston 2016 Howell 2023

Complications + management (what to watch for and how to reduce risk)

  • The most common reported complications include bleeding, infection, and scarring, and their prevention is related to meticulous technique and appropriate site/size selection. Nischal 2008

  • In areas of high functional or aesthetic impact (nail unit, scalp), compartment planning and sample orientation aim to reduce permanent sequelae without sacrificing diagnosis. Grover 2018 Pinedo-Moraleda 2023

  • In conditions where an insufficient biopsy necessitates repeat biopsy (panniculitis, vasculitis, early mycosis fungoides), the main “cost” of poor technique is not the wound itself, but the diagnostic delay. Tomasini 2013 Lee 2023

Bibliography and sources

 

Content reviewed by:
Dr. Rodolfo Suárez
Medical Pathologist and Dermatologist
Master's Degree in Advanced Cutaneous Pathology
19/03/2026
22/03/2026
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