Interactive Case Study - March 2026

52-year-old man with subcutaneous masses on the abdomen

Saad Nadeem MBA, MHA

Helen Chen, MD

John Griffin, MD, MA, FAAD

A 52-year-old male presents with multiple 2-3 cm firm subcutaneous masses on the abdomen. The patient has a long-standing history of insulin dependent diabetes mellitus and has been managed with insulin injections for several years. Incisional biopsy was obtained and stained with hematoxylin and eosin (Figure 1-2) and Congo red (Figure 3).

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Figure 1: H&E 2x

Figure 2: H&E 20x

Figure 3: Congo Red Stain Viewed without Polarized Light

Figure 4: Congo Red Stain Viewed with Polarized Light

Given the clinical presentation and the microscopic findings, what is the most likely diagnosis?

Desmoid fibromatosis

Lipohypertrophy

Localized insulin-derived amyloidosis

Nodular fasciitis

Subcutaneous insulin resistance syndrome

What is the most appropriate next step in diagnosis?

Genotyping of NLRP3 gene

In situ hybridization to evaluate for monotypic kappa or lambda light chain

Liquid chromatography tandem mass spectrometry (LC MS/MS) of deposits

Serum protein electrophoresis with immunofixation

X-ray diffraction analysis of deposits

What is the most appropriate next step in the management of this patient?

Change the site of insulin injection

Discontinue insulin and switch to oral hypoglycemic agents

Initiate systemic corticosteroid therapy

Refer for surgical excision of all nodules

Start topical tacrolimus treatment

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Acknowledgements

Author Profiles

Saad Nadeem MBA, MHA

Houston Methodist Willowbrook.

Saad Nadeem MBA, MHA is a third year medical student at Texas A&M College of Medicine. Originally from Houston, Saad Nadeem grew up and spent most of life in Clear Lake, Texas. In 2023, Saad Nadeem graduated from the University of Houston as a triple major and triple minor with a 4.0 GPA. Saad is currently a third-year medical student with a strong interest in practicing in Houston and becoming someone who can give back to the community.

Helen Chen, MD

Texas Tech University Health Sciences Center Department of Dermatology

Helen Chen, MD, is a PGY-3 resident at Texas Tech University Health Sciences Center. Originally from Mission, TX, in the Rio Grande Valley, she completed her undergraduate and medical education at Texas A&M University. Dr. Chen’s interests include hiking, board games, and spending time with her fiancé and her cat, Momo.

John Griffin, MD, MA, FAAD

Kelsey-Seybold Clinic

John Griffin is the managing physician of dermatopathology at Kelsey-Seybold Clinic, a multi-specialty group practice in Houston, TX, where he also practices clinical dermatology with a focus on complex medical dermatology and contact dermatitis. He obtained his medical degree from UT McGovern Medical School and completed a dermatology residency at Mayo Clinic in Rochester, MN, and a dermatopathology fellowship at SUNY Downstate / Ackerman Academy in New York. He serves as clinical faculty at Texas A&M College of Medicine and UT McGovern Medical School in Houston.

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Interactive Case Study - March 2026

Acknowledgements

Author Profiles

52-year-old man with subcutaneous masses on the abdomen

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