Extensive dystrophic calcinosis in dermatomyositis with concurrent breast carcinoma: an imaging pitfall

Abstract

Dermatomyositis is a rare idiopathic inflammatory myopathy. Long-standing disease may be complicated by progressive dystrophic calcinosis. The association of extensive calcinosis with underlying malignancy remains exceptionally rare and diagnostically challenging.

A 63-year-old woman with a 15-year history of dermatomyositis presented with rapidly progressive diffuse cutaneous calcinosis and a palpable right breast mass. Mammography identified a spiculated mass classified BI-RADS 5, embedded within extensive mammary macrocalcifications. Ultrasound-guided core needle biopsy confirmed invasive carcinoma of no special type (NST) (SBR grade II, ER−/PR−, HER2−). Staging CT scan and bone scintigraphy demonstrated no distant metastasis but revealed diffuse soft-tissue calcinosis of the abdominal and pelvic walls. The patient was subsequently referred to the oncology department for further staging and multidisciplinary management.

This case highlights the diagnostic pitfall of extensive mammary calcinosis in DM, which may obscure an underlying mass or architectural distortion rather than directly mimic malignant microcalcifications. Any discrete mass or architectural distortion identified within or adjacent to a calcinotic background warrants targeted ultrasound and image-guided biopsy. Oncological surveillance in dermatomyositis should be age-appropriate and risk-stratified, reflecting the fact that malignancy risk is highest around the time of diagnosis.

Introduction

Dermatomyositis is a heterogeneous autoimmune disease characterised by a diffuse inflammatory process involving the cutaneous tissue, striated musculature, and multiple soft tissue compartments [1].

While calcinosis complicates the course of 10–40% of juvenile-onset DM patients, its occurrence in adult-onset dermatomyositis is considerably less frequent, making the extent of calcinosis observed in our patient particularly noteworthy [2].

Cancer is identified in 15–30% of patients with DM, making oncological screening an integral part of disease management [3]. Among the malignancies reported, lung, ovarian, and breast cancers are the most prevalent, the latter being directly relevant to the present case [4].

We report a case of adult-onset dermatomyositis complicated by extensive soft-tissue calcinosis, in which radiological workup led to the diagnosis of an unsuspected breast carcinoma.

Case report

A 63-year-old woman was referred to our department for rapidly worsening diffuse cutaneous swellings. She had been followed for 15 years for DM, diagnosed at age 48 on the basis of proximal muscle weakness, heliotrope rash, Gottron's papules, elevated muscle enzymes, myopathic electromyogram, and muscle biopsy showing perifascicular atrophy with perivascular inflammatory infiltrate. Over the course of follow-up, she had received successive courses of systemic corticosteroids. Disease activity had remained partially controlled, with intermittent flares and the gradual development of subcutaneous calcific nodules at the limbs and trunk.

At the current presentation, the patient reported a several-week history of a painless, incidentally discovered mass in the right breast. Physical examination revealed multiple firm, indurated calcific plaques and nodules distributed diffusely over the shoulders, flanks, and abdominal wall, with involvement of the pelvic walls. Several nodules were ulcerated with extrusion of chalky material. Palpation of the right breast identified a hard, poorly defined, non-tender mass at the junction of the lower quadrants, approximately 3 cm in greatest dimension, without nipple discharge or clinically palpable axillary lymphadenopathy.

Inflammatory markers were mildly elevated (CRP 24 mg/L). Muscle enzymes were moderately raised (CK 3 × upper limit of normal). Serum calcium, phosphate, and parathyroid hormone were within normal limits. CA 15-3 was elevated at 78 IU/mL (normal < 30 IU/mL).

Bilateral mammography was performed on a background of scattered fibroglandular densities (ACR density category B). It demonstrated a spiculated mass at the junction of the lower quadrants of the right breast, measuring 28 × 21 mm, without associated architectural distortion beyond the margins of the mass itself. The mass and the surrounding right breast parenchyma were embedded within extensive, coarse, confluent macrocalcifications; no additional fine pleomorphic or fine linear/branching microcalcifications suspicious for malignancy were identified separately from this dystrophic calcification pattern. The overall mammographic appearance was classified BI-RADS 5. The left breast showed diffuse bilateral macrocalcifications of similar dystrophic morphology but no focal suspicious mass, architectural distortion, or malignant-type microcalcifications (Fig. 1). Targeted ultrasound of the right breast mass demonstrated a hypoechoic, irregular lesion with ill-defined margins, measuring approximately 2–3 cm on grayscale imaging, corresponding to the mammographically identified spiculated mass; no color Doppler flow was demonstrated within the lesion (Fig. 2).

Fig. 1.

Bilateral mammography in mediolateral oblique (MLO) and craniocaudal (CC) views demonstrating a spiculated, ill-defined mass at the junction of the lower quadrants of the right breast, classified BI-RADS 5 (Green arrows), with diffuse macrocalcifications involving both breasts bilaterally, consistent with dystrophic calcinosis in the setting of dermatomyositis. The left breast shows no focal suspicious mass.

Fig. 2.

Grayscale ultrasound of the right breast mass in two separate caliper acquisitions (A, B) showing a hypoechoic, irregular, ill-defined lesion. No color Doppler flow was demonstrated within the lesion.

Ultrasound-guided core needle biopsy (14G, 5 cores) confirmed invasive carcinoma of no special type (NST), SBR grade II, with oestrogen receptor negativity (< 1%), progesterone receptor negativity (< 1%), HER2 negativity (score 1+), and Ki-67 index of 40%. No lymphovascular invasion was identified. Dystrophic calcifications were also noted on pathological examination, predominantly peritumoral in distribution.

Staging thoraco-abdomino-pelvic CT scan excluded hepatic, pulmonary, and osseous metastasis. Strikingly, imaging revealed extensive soft-tissue macrocalcifications distributed along the thoracic wall, the anterior and lateral abdominal walls, and throughout the pelvic walls, with further distal extension to the thighs bilaterally, reflecting the remarkable systemic burden of DM-related dystrophic calcinosis (Fig. 3A–D). The patient was subsequently referred to the oncology department for further staging and multidisciplinary management.

Fig. 3.

Axial CT images at four levels (thorax, upper abdomen, pelvis, thighs) demonstrating extensive, bilateral dystrophic macrocalcifications consistent with DM-related calcinosis, with no osseous or visceral metastasis identified at the levels imaged. (A) Thoracic level: macrocalcifications along the bilateral lateral chest wall. (B) Upper abdominal level: hyperdense macrocalcifications in the bilateral lateral and posterior abdominal soft tissues. (C) Pelvic level: massive, confluent macrocalcifications involving both pelvic sidewalls. (D) Thigh level: massive, confluent macrocalcifications of the subcutaneous and muscular compartments.

Discussion

The association between DM and malignancy, first reported in 1916, has since been validated by case-control studies and large-scale epidemiological cohorts [5].

The pathogenesis of dystrophic calcinosis in DM remains incompletely understood, with proposed mechanisms including chronic tissue inflammation, hypoxia-driven release of phosphate-binding proteins from damaged cells, and mitochondrial dysfunction, favoring local precipitation of hydroxyapatite and amorphous calcium phosphate within previously injured soft tissue [6]. Prolonged, incompletely controlled disease activity is a recognised risk factor for calcinosis development and progression, consistent with the fifteen-year history of intermittently controlled disease that preceded the extensive calcinotic burden observed in our patient [6].

The paraneoplastic nature of DM is further substantiated by myositis-specific autoantibodies, most notably anti-transcription intermediary factor 1-gamma (anti-TIF1-γ), which has been associated with an approximately nine-fold increased risk of malignancy, with a pooled sensitivity of 78% and specificity of 89% for cancer-associated dermatomyositis in a systematic review and meta-analysis [7]. Breast carcinoma is among the malignancies most frequently reported in anti-TIF1-γ-positive patients, lending biological plausibility to a paraneoplastic mechanism in TIF1-γ-associated dermatomyositis more broadly. In our patient, however, the fifteen-year interval between dermatomyositis diagnosis and the detection of breast carcinoma, together with the absence of autoantibody testing and of any documented renewed disease activity temporally related to the malignancy, argues against a direct paraneoplastic relationship. The carcinoma is therefore best regarded as a concurrent, rather than causative, association in this case.

Namas et al. [8] first documented bilateral mammary calcinosis in DM on mammography, without associated malignancy or systemic calcinosis. Fernandez et al. (2023) [9] later refined this using digital breast tomosynthesis, localising calcium deposits within the pectoralis major muscle and subcutaneous tissue bilaterally, again without associated carcinoma or CT evidence of systemic calcinosis.

Azhideh et al. [10] represent the closest imaging parallel to our case, documenting a virtually identical topographic distribution of calcinosis: bilateral mammary involvement on mammography with diffuse extension to the abdominal wall, pelvic walls, and lower limbs on CT. The clinical, radiological, and histological characteristics of these three previously reported cases, together with the present case, are summarized in Table 1.

Table 1.

Comparative review of cases of dermatomyositis with diffuse calcinosis and mammary involvement: from isolated calcinosis to associated breast carcinoma.

Author	Age	Calcinosis extent	Breast findings	Histology / Malignancy
Namas et al. [8]	71 y	Bilateral mammary calcinosis on mammography	Bilateral mammary macrocalcifications; No focal suspicious mass	No biopsy: No malignancy reported
Fernandez et al. [9]	49 y	Bilateral mammary calcinosis (pectoralis major + subcutaneous) Calcinosis universalis phenotype	Extensive bilateral dystrophic macrocalcifications on tomosynthesis; No suspicious mass	No biopsy indicated: No malignancy reported
Azhideh et al. [10]	45 y	Diffuse calcinosis cutis: Bilateral mammary + abdominal + pelvic + lower limbs on CT	Bilateral mammary macrocalcifications on mammography; No focal suspicious mass	No biopsy: No malignancy reported
Present case	63 y	Diffuse bilateral mammary + thoracic wall + abdominal wall + pelvic walls + thighs Fully documented on CT	Spiculated mass on the right breast measuring 28 × 21 mm: BI-RADS 5 + Bilateral mammary macrocalcifications	Invasive carcinoma of no special type (NST) SBR grade II

Unlike the three reported cases, our patient harbored a concurrent breast carcinoma within the calcinotic background. A spiculated BI-RADS 5 mass identified on mammography prompted ultrasound-guided biopsy, which confirmed invasive carcinoma of no special type (NST). To our knowledge, no prior publication has reported the simultaneous combination of diffuse bilateral mammary calcinosis, extensive abdomino-pelvic soft-tissue calcinosis on CT, and a histologically proven breast carcinoma in a patient with adult-onset DM.

From an imaging standpoint, the coexistence of extensive dystrophic calcinosis and breast carcinoma illustrates a specific diagnostic pitfall. Dystrophic calcifications are conventionally regarded as a typically benign mammographic morphology, appearing coarse and irregular and generally easier to distinguish from the fine pleomorphic or fine linear branching microcalcifications that raise suspicion for malignancy [11]. However, when calcinosis is extensive and confluent, as in our patient, it may obscure an underlying mass or mimic architectural distortion, increasing the risk that a genuine malignant lesion is overlooked, or, conversely, that indeterminate benign-appearing calcifications are biopsied unnecessarily. This underlines the importance of correlating mammographic findings with clinical palpation and of proceeding to targeted ultrasound and image-guided biopsy whenever a discrete mass or architectural distortion is identified within or adjacent to a calcinotic background, regardless of the presence of overlying benign-appearing macrocalcifications.

The management of dystrophic calcinosis itself remains challenging, as no pharmacological agent has demonstrated consistent efficacy, and surgical excision remains reserved for large, painful, or ulcerated lesions [12]. In our patient, the diagnostic priority was oncological: identification of the underlying breast carcinoma took precedence over calcinosis-directed therapy, underscoring that the discovery of extensive calcinosis should not divert clinical attention from a thorough and systematic search for an associated malignancy.

Dystrophic calcinosis in dermatomyositis does not preclude concurrent malignancy and may even conceal it. Any discrete mass or architectural distortion identified within or adjacent to a calcinotic background should be assessed according to standard radiological criteria and, where appropriately suspicious, undergo image-guided biopsy; this case underscores the value of maintaining a high index of suspicion for breast malignancy in patients with extensive calcinotic change.

Conclusion

This case illustrates the rare, and to our knowledge previously unreported, coexistence of diffuse dystrophic calcinosis involving the breast and the abdomino-pelvic soft tissues with a histologically proven invasive breast carcinoma in a patient with a 15-year history of adult-onset dermatomyositis. It highlights two key lessons for clinical practice. First, although dystrophic calcinosis is classically regarded as a radiologically benign entity, when extensive and confluent it may obscure or mimic a suspicious breast lesion, underscoring the need for systematic correlation between clinical, mammographic, and ultrasound findings, and prompt recourse to image-guided biopsy whenever a focal mass or architectural distortion is identified. Second, malignancy risk in dermatomyositis is highest around the time of diagnosis, and oncological surveillance should therefore be age-appropriate and risk-stratified rather than applied as a uniform, indefinite protocol; the extent of calcinosis observed in our patient should not divert clinical attention from this risk-based approach. Heightened radiological and clinical vigilance, combined with prompt image-guided biopsy of any discrete mass or architectural distortion identified within or adjacent to a calcinotic background, therefore appears essential in the management of these patients.

Patient consent

Written informed consent was obtained from the patient for the anonymized information to be published in this article.